If humans disappeared tomorrow, what would happen in the animal kingdom? This video clip looks at the effects of human absence on animal population and speculates about the Darwinian battle that would result if humans were suddenly removed from the ecosystem.

Fish with a penis head

Speaking of fish, this one has an … odd anatomy. Researchers in Vietnam's Mekong Delta reported the discovery of a fish with a penis on its head in August 2012.

Yep, a penis. And it's not just any penis &mdash the organ includes a jagged hook for grabbing females during sex. (The female fish's genitals are located on her throat.)

The species is named Phallostethus cuulong and is one of few fish that fertilizes eggs inside the female's body rather than outside. The nasty-looking hook appendage seems to have evolved to ensure the male's sperm get to the right place. [7 Sexy Facts About Sperm]

8 Top Websites Where Kids Can Learn About Animals

One subject most kids enjoy learning about is animals. Picture books with animal characters are firm favorites with the younger crowd, and non-fiction books about animals are popular with curious older kids. Kids also love to observe animals, in real life visits to the zoo perhaps, or via some of the well-made documentaries available. Children with access to companion animals learn lots about the special joy such animals bring to our lives.

There are a number of fascinating websites devoted to helping us learn about animals. Here are some you might like to explore with your kids.

Looking for book and reading ideas? Sign up for our Scholastic Parents newsletter.

Children and adults alike can't help grinning delightedly when they see baby animals. Help your kids explore this website, devoted to the newest, cutest baby animals from the world's accredited zoos and aquariums. It's a great place to play conversation games like choosing the cutest one or deciding on a fantasy pet. It might also make a good jumping-off point for research on animals or a school project. If your child can't get enough of baby animals, there's My Encyclopedia of Baby Animals, a squeal-worthy guide to the most adorable animals around.

National Geographic and National Geographic Kids
Both sites offer stacks of resources on animals, including videos. Young children will benefit from your help with some of the heavier reading, and there'll be lots of opportunities for you to discuss what you learn. Kids also will be mesmerized with the wild animals in 101 Animal Secrets and LEGO Nonfiction: Big Book of Animals, which burst with gorgeous photographs.

Australia's ABC Splash
This is a rabbithole of a website where we can easily lose track of time! As well as lots of general educational resources, including videos, interactive games and digi-books, it offers helpful materials on animals like this one on Remarkable Animal and Plant Life Cycles. Discover the animals native to the vast continent of Australia with A True Book: Australia and Oceania.

Walking With Dinosaurs
Despite being better suited for older children, young dinosaur fans will still adore looking at the images and videos about dinosaurs on this BBC site. Moms and dads can help youngsters read some of the fascinating fact sheets seen by clicking on images. Hungry for more? Young readers will gobble up the full-bleed photos and fun facts in Fly Guy Presents: Dinosaurs, while older readers (grades 3 and up) will revel in the "terrifying truths" revealed about the giant reptiles who ruled the skies, land and sea in The Science of Dinosaurs series.

World Wildlife Fund
As well as discovering more about endangered species and the important work the WWF does, this website has lots of great educational materials about animals. Check out tabs like Species, browse the excellent close-up images, and find the answers to questions like Why Are Sloths Slow? To learn more about the precious animals protected by the WWF, read the A True Book: The Most Endangered series, which features educational books on gorillas, big cat species, polar bears, and more.

I wrote about ARKive back in 2010, and it's still one of my favorite web spaces. Again, children will get more from this site if their parents spend time discussing and sharing it with them. You can browse by topics, species, habitats, and more, but make sure to check out the education section. I love that it has materials suitable even for 5- to 7-year-olds, with children encouraged to learn through activities like making animal masks. For more creative activities, try our animal-related Klutz kits — your creative child can make animal paper lanterns and miniature animal plushies.

Kids Planet
If some of the websites above seem a little too serious for your kids, help them visit Kids Planet. As well as finding some excellent fact sheets, here they can play animal-themed games, like Who Am I, where they need to identify animal sounds. For another lighthearted approach to learning about animals, try the What If You Had Animal. series, which teaches kids fun facts about animals as they try to imagine what it would be like to have a shark's teeth or a porcupine's quills.

Switch Zoo
Switch Zoo is another site where the learning is slightly disguised by fun! Children can play animal games, create their own wacky new animals, even solve jigsaw puzzles. Can't you just imagine the fun kids will have making a unique animal and imagining its diet, its habitat, and its special features? For even more educational fun, try The Magic School Bus Back in Time with the Dinosaurs Science Kit — your child can mold fossils, build a dinosaur replica, and more, all while learning!

Sharing websites like these with our kids is a wonderful way to demonstrate safe online behavior, as well as our own enthusiasm for learning. Follow up with a visit to your local library or zoo to extend the experience. Searching publisher websites will bring an amazing array of animal-themed bookish goodness, where you're sure to find resources just right for your children.


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Baby dinosaurs hatched in the Arctic 70 million years ago

The discovery of teensy baby dinosaur bones and teeth in the Alaskan Arctic reveals that dinosaurs nested and incubated their eggs there 70 million years ago.

Tasmanian devils wipe out colony of little penguins in major conservation backfire

Tasmanian devils introduced to Maria Island for their own conservation have created an ecological disaster in their new home by wiping out an entire population of little penguins.

Black bears: The most common bear in North America

American black bears are the smallest and most common bear in North America. They are highly adaptable, with a diet that includes honey and moose.

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These spiders take down snakes hundreds of times their size

Venomous spiders prey upon snakes many times their size, a new study finds — and often emerge victorious against snakes as venomous as they are.

Photos: Spiders feast on deadly snakes

From the Goliath birdeater tarantula to black widows, spiders are not shy around deadly snakes, often taking down the juveniles and feasting on their meaty bodies for days.

Is every spiderweb unique?

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Ancient giant rhino was one of the largest mammals ever to walk Earth

Paleontologists in China found the skull, jaw and a few vertebrae belonging to one of the largest land mammals that ever lived.

This 'ancient' monster fish may live for 100 years

A detailed look at coelacanths' scales reveals that this ancient lineage of fish may live to be 100 years old.

World's first bionic vulture created

Lifesaving surgery gives a rare bird a leg up.

Never-before-seen brain cells discovered in mice. They're called gorditas.

Researchers discovered new cells after switching on stem cells in the mouse brain.

'Ballooning' spiders leave behind sea of silk after flood in Australia

The phenomenon is "surprisingly common" after floods, experts say.

'Strange beast' in amber is a very weird lizard

A tiny amber-locked skull that looks like a bird's is actually a lizard's, new fossil evidence shows.

Gold miners discover giant skeletons of 3 woolly mammoths

Gold miners have discovered three partial skeletons of three woolly mammoths , which may have been part of the same family.

Toxic hairy caterpillars invade Maine

The tiny caterpillars have thin poisonous hairs that can cause poison-ivy-like rashes and breathing problems in some people.

Cottonmouth snakes: Facts about water moccasins

By Jessie Szalay, Patrick Pester

Cottonmouths, or water moccasins, are venomous snakes in North America that display white mouths when threatened.

Scientists unravel mystery of echidnas' bizarre 4-headed penis

Scientists have finally solved a longstanding mystery surrounding the bizarre 4-headed penises of echidnas using CT scans.

Crows understand the 'concept of zero' (despite their bird brains)

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Will humans ever learn to speak whale?

Cutting-edge technology is helping researchers collect and analyze whale communication.

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When the Nazis Tried to Bring Animals Back From Extinction

Born to the director of the Berlin Zoo, Lutz Heck seemed destined for the world of wildlife. But instead of simply protecting animals, Heck had a darker relationship with them: he hunted and experimented with them.

In the new movie The Zookeeper’s Wife (based on a nonfiction book of the same title by Diane Ackerman), Heck is the nemesis of Warsaw zookeepers Antonina and Jan Zabinski, who risk their lives to hide Jews in cages that once held animals. All told, the couple smuggled around 300 Jewish people through their zoo. Not only was Heck tasked with pillaging the Warsaw Zoo for animals that could be sent to Germany, he was also at work on project that began before the Nazis came to power: reinvent nature by bringing extinct species back to life.

Lutz and his younger brother, Heinz, grew up surrounded by animals and immersed in animal breeding, beginning with small creatures like rabbits. At the same time that the boys learned more about these practices, zoologists around Europe were engaged in debates about the role of humans in preventing extinction and creating new species.

“It was kicked off by all kinds of what we would consider quite weird experiments. People were trying to breed ligers and tigons,” says Clemens Driessen, a researcher in cultural geography at Wageningen University and Research in the Netherlands.

While breeders’ imaginations ran wild with thoughts of new species to create, closer to home, European bison, known as wisent, were going extinct in the wild. Scientists began to consider the role of zoos could play in keeping the species alive—and in Germany, to combine those answers with theories about the supposed “purity” of long-gone landscapes.

Should wisent be revitalized using American bison as breeding stock? Would the resulting offspring still be considered proper bison? As they grew older, the Heck brothers were immersed in these same questions.

According to an article written by Driessen and co-author Jamie Lorimer, Heinz saw the extinction of the wisent as the natural progression of the result of nomadic tribes overhunting. His brother, on the other hand, became more and more interested in what he considered to be “primeval German game”—an interest increasingly shared by Nazis who sought a return to a mythic German past free of racial impurities.

In his autobiography Animals: My Adventure Lutz describes being fascinated by animals he associated with that mythical past, especially wisent and the formidable aurochs.

Lutz Heck with a scaly anteater, 1940 (Sueddeutsche Zeitung Photo / Alamy Stock Photo)

Aurochs were large, horned cattle that went extinct in 1627 from excessive hunting and competition from domesticated cattle. The brothers believed they could recreate the animals through back-breeding: choosing existing cattle species for the right horn shape, coloration and behavior, then breeding them until they had something approximating the original animal. This was before the discovery of DNA’s double helix, so everything the brothers looked to for information on aurochs was from archaeological finds and written records. They believed that since modern cattle descended from aurochs, different cattle breeds contained the traces of their more ancient lineage.

“What my brother and I now had to do was to unite in a single breeding stock all those characteristics of the wild animal which are now found only separately in individual animals,” Heck wrote in his book. Their plan was the inverse of Russian experiments to create domesticated foxes through selective breeding—rather than breed forward with particular traits in mind, they thought they could breed backwards to eliminate the aspects of their phenotype that made them domesticated. (Similar experiments have been picked back up by modern scientists hoping to create aurochs once more, and by scientists trying to recreate the extinct quagga. Researchers disagree over whether this type of de-extinction is possible.)

The brothers traveled the continent, selecting everything from fighting cattle in Spain to Hungarian steppe cattle to create their aurochs. They studied skulls and cave paintings to decide what aurochs should look like, and both claimed success at reviving aurochs by the mid-1930s. Their cattle were tall with large horns and aggressive personalities, capable of surviving with limited human care, and in modern times would come to be called Heck cattle. The animals were spread around the country, living everywhere from the Munich Zoo to a forest on the modern-day border of Poland and Russia.

But despite their shared interest in zoology and animal husbandry, the brothers’ paths diverged greatly as the Nazis rose to power. In the early 1930s, Heinz was among the first people interned at Dachau as a political prisoner for suspected membership in the Communist Party and his brief marriage to a Jewish woman. Though Heinz was released, it was clear he would never be a great beneficiary of Nazi rule, nor did he seem to support their ideology focused on the purity of nature and the environment.

Lutz joined the Nazi Party early in its reign, and earned himself a powerful ally: Hermann Göring, Adolf Hilter’s second-in-command. The two men bonded over a shared interest in hunting and recreating ancestral German landscapes. Göring amassed political titles like trading cards, serving in many positions at once: he became the prime minister of Prussia, commander in chief of the Luftwaffe, and Reich Hunt Master and Forest Master. It was in this last position that he bestowed the title of Nature Protection Authority to Lutz, a close friend, in 1938.

Hermann Göring (Wikimedia Commons)

“Göring saw the opportunity to make nature protection part of his political empire,” says environmental historian Frank Uekotter. “He also used the funds [from the Nature Protection Law of 1935] for his estate.” The law, which created nature reserves, allowed for the designation of natural monuments, and removed the protection of private property rights, had been up for consideration for years before the Nazis came to power. Once the Nazis no longer had the shackles of the democratic process to hold them back, Göring quickly pushed the law through to enhance his prestige and promote his personal interest in hunting.

Lutz continued his back-breeding experiments with support from Göring, experimenting with tarpans (wild horses, whose Heck-created descendants still exist today) and wisent. Lutz’s creations were released in various forests and hunting reserves, where Göring could indulge his wish to recreate mythic scenes from the German epic poem Nibelungenlied (think the German version of Beowulf), in which the Teutonic hero Siegfried kills dragons and other creatures of the forest.

“Göring had a very peculiar interest in living a kind of fantasy of carrying spears and wearing peculiar dress,” Driessen says. “He had this eerie combination of childish fascination [with the poem] with the power of a murderous country behind it.” In practical terms, this meant seizing land from Poland, especially the vast wilderness of Białowieża Forest, then using it to create his own hunting reserves. This fit into the larger Nazi ideology of lebensraum, or living space, and a return to the heroic past.

“On the one hand National Socialism embraced modernity and instrumental rationality something found in the Nazi emphasis on engineering, eugenics, experimental physics and applied mathematics,” write geographers Trevor Barnes and Claudio Minca. “On the other hand was National Socialism’s other embrace: a dark anti-modernity, the anti-enlightenment. Triumphed were tradition, a mythic past, irrational sentiment and emotion, mysticism, and a cultural essentialism that turned easily into dogma, prejudice, and much, much worse.”

In 1941 Lutz went to the Warsaw Zoo to oversee its transition to German hands. After selecting the species that would be most valuable to German zoos, he organized a private hunting party to dispatch with the rest. “These animals could not be recuperated for any meaningful reason, and Heck, with his companions, enjoyed killing them,” writes Jewish studies scholar Kitty Millet.

Millet sees an ominous connection to the Nazi ideology of racial purity. “The assumption was that the Nazis were the transitional state to the recovery of Aryan being,” Millet wrote in an email. In order to recover that racial purity, says Millet, “nature had to be transformed from a polluted space to a Nazi space.”

While Driessen sees little direct evidence of Lutz engaging with those ideas, at least in his published research, Lutz did correspond with Eugen Fischer, one of the architects of Nazi eugenics.

But his work creating aurochs and wisent for Göring shared the same conclusion as other Nazi projects. Allied forces killed the wild animals as they closed in on the Germans at the end of the war. Some Heck cattle descended from those that survived the end of the war in zoos still exist, and their movement around Europe has become a source of controversy that renews itself every few years. They’ve also been tagged as a possible component of larger European rewilding programs, such as the one envisioned by Stichting Taurus, a Dutch conservationist group Stichting Taurus.

With scientists like the Dutch and others considering the revival of extinct wildlife to help restore disturbed environments, Uekotter thinks Heck’s role in the Nazi Party can serve as a cautionary tale. “There is no value-neutral position when you talk about the environment. You need partners and, [compared to gridlock that happens in democracy,] there is a lure of the authoritarian regime that things are all of a sudden very simple,” Uekotter says. “The Nazi experience shows what you can end up with if you fall for this in a naïve way.”

How Did That Happen?

Not counting the domestic dog, who has been our partner for at least 15,000 years, the animal domestication process started about 12,000 years ago. Over that time, humans have learned to control animal access to food and other necessities of life by changing the behaviors and natures of their wild ancestors. All of the animals that we share our lives with today, such as dogs, cats, cattle, sheep, camels, geese, horses, and pigs, started out as wild animals but were changed over the hundreds and thousands of years into more sweet-natured and tractable partners in farming.

And it's not just behavioral changes that were made during the domestication process--our new domesticated partners share a suite of physical changes, changes that were bred it either directly or indirectly during the domestication process. A reduction in size, white coats, ​and floppy ears are all mammalian syndrome characteristics bred into several of our domestic animal partners.

The birth of half-human, half-animal chimeras

In H. G. Wells's The Island of Doctor Moreau, the shipwrecked hero Edward Pendrick is walking through a forest glade when he chances upon a group of two men and a woman squatting around a fallen tree. They are naked apart from a few rags tied around their waist, with "fat, heavy, chinless faces, retreating foreheads, and a scant bristly hair upon their foreheads." Pendrick notes that "I never saw such bestial looking creatures."

As Pendrick approaches, they attempt to talk to him, but their speech is "thick and slopping" and their heads sway as they speak, "reciting some complicated gibberish". Despite their clothes and their appearance, he perceives the "irresistible suggestion of a hog, a swinish taint" in their manner. They are, he concludes, "grotesque travesties of men".

Wandering into Doctor Moreau's operating room one night, Pendrick eventually uncovers the truth: his host has been transforming beasts into humans, sculpting their bodies and their brains into his own image. But despite his best efforts he can never eliminate their most basic instincts, and the fragile society soon regresses to dangerous anarchy, leading to Moreau's death.

It is 120 years since Wells first published his novel, and to read some recent headlines you would think that we are veering dangerously close to his dystopic vision. "Frankenstein scientists developing part-human part-animal chimera," exclaimed the UK's Daily Mirror in May 2016. "Science wants to break down the fence between man and beast," the Washington Times declared two months later, fearing that sentient animals would soon be unleashed on the world.

The hope is to implant human stem cells in an animal embryo so that it will grow specific human organs. The approach could, in theory, provide a ready-made replacement for a diseased heart or liver &ndash eliminating the wait for a human donor and reducing the risk of organ rejection.

It's going to open up a new understanding of biology

These bold and controversial plans are the culmination of more than three decades of research. These experiments have helped us understand some of the biggest mysteries of life, delineate the boundaries between species, and explore how a ragbag bunch of cells in the womb coalesce and grow into a living, breathing being.

With new plans to fund the projects, we are now reaching a critical point in this research. "Things are moving very fast in this field today," says Janet Rossant at the Hospital for Sick Children in Toronto, and one of the early pioneers of chimera research. "It's going to open up a new understanding of biology."

That is, provided we can resolve some knotty ethical issues first &ndash questions that may permanently change our understanding of what it means to be human.

For millennia, chimeras were literally the stuff of legend. The term comes from Greek mythology, with Homer describing a strange hybrid "of immortal make, not human, lion-fronted and snake behind, a goat in the middle". It was said to breathe fire as it roamed Lycia in Asia Minor.

At least 8% of non-identical twins have absorbed cells from their brother or sister

In reality, chimeras in science are less impressive. The word describes any creature containing a fusion of genetically-distinct tissues. This can occur naturally, if twin embryos fuse soon after conception, with striking results.

Consider the "bilateral gynandromorphs", in which one side of the body is male, the other female. These animals are essentially two non-identical twins joined down the centre. If the two sexes have wildly different markings &ndash as is the case for many birds and insects &ndash this can lead to a bizarre appearance, such as a northern cardinal that had grown bright red plumage on half of its body, while the rest was grey.

Most often, however, the cells mix to form a subtler mosaic across the whole body, and chimeras look and act like other individuals within the species. There is even a chance that you are one yourself. Studies suggest that at least 8% of non-identical twins have absorbed cells from their brother or sister.

The mixed bag of animals from Greek legends certainly cannot be found in nature. But this has not stopped scientists from trying to create their own hybrid chimeras in the lab.

Janet Rossant, then at Brock University, Canada, was one of the first to succeed. In 1980, she published a paper in the journal Science announcing a chimera that combined two mice species: an albino laboratory mouse (Mus musculus) and a Ryukyu mouse (Mus caroli), a wild species from east Asia.

Previous attempts to produce a hybrid "interspecific" chimera often ended in disappointment. The embryos simply failed to embed in the uterus, and those that did were deformed and stunted, and typically miscarried before they reached term.

We showed you really could cross species boundaries

Rossant's technique involved a delicate operation at a critical point in pregnancy, around four days after mating. At this point, the fertilised egg has divided into a small bundle of cells known as the blastocyst. This contains an inner cell mass, surrounded by a protective outer layer called the trophoblast, which goes on to form the placenta.

Working with William Frels, Rossant took the M. musculus and injected it with the inner cell mass of the other species, M. caroli. They then implanted this mixed bag of cells back into the M. musculus mothers. By ensuring that the M. musculus trophoblast remained intact, they ensured that the resulting placenta would match the mother's DNA. This helped the embryo embed in the uterus. Next they sat back and waited 18 days for the pregnancies to unfold.

It was a resounding success of the 48 resulting offspring, 38 were a blend of tissues from both species. "We showed you really could cross species boundaries," Rossant says. The blend was apparent in the mice's coats, with alternating patches of albino white from the M. musculus and the tawny stripes of the M. caroli.

Even their temperaments were noticeably different from their parents. "It was quite obviously a weird mixture," says Rossant. "M. caroli are very jumpy: you would need to put them at the bottom of a garbage can so they don't jump out at you, and you'd handle them with forceps and leather gloves." The M. musculus were much calmer. "The chimeras were somewhat in between."

With today's understanding of neuroscience, Rossant thinks this could help us to explore the reasons why different species act the way they do. "You could map the behavioural differences against the different regions of the brain that were occupied by the two species," she says. "I think that could be very interesting to examine."

Time magazine described the geep as "a zookeeper's prank: a goat dressed in a sweater of angora"

In her early work Rossant used these chimeras to probe our basic biology. Back when genetic screening was in its infancy, the marked differences between the two species helped to identify the spread of cells within the body, allowing biologists to examine which elements of the early embryo go on to create the different organs.

The two lineages could even help scientists investigate the role of certain genes. They could create a mutation in one of the original embryos, but not the other. Watching the effect on the resulting chimera could then help tease apart a gene's many functions across different parts of the body.

Using Rossant's technique, a handful of other hybrid chimeras soon emerged kicking and mewling in labs across the world. They included a goat-sheep chimera, dubbed a geep. The animal was striking to see, a patchwork of wool and coarse hair. Time described it as "a zookeeper's prank: a goat dressed in a sweater of angora."

Rossant also advised various conservation projects, which hoped to use her technique to implant embryos of endangered species into the wombs of domestic animals. "I'm not sure that has ever entirely worked, but the concept is still there."

Now the aim is to add humans to the mix, in a project that could herald a new era of "regenerative medicine".

For two decades, doctors have tried to find ways to harvest stem cells, which have the potential to form any kind of tissue, and nudge them to regrow new organs in a petri dish. The strategy would have enormous potential for replacing diseased organs.

The aim is to create chimera animals that can grow organs to order

"The only problem is that, although these are very similar to the cells in the embryo, they are not identical," says Juan Carlos Izpisua Belmonte at the Salk Institute for Biological Studies in La Jolla, California. So far, none have been fit for transplantation.

Izpisua Belmonte, and a handful of others like him, think the answer is lurking in the farmyard. The aim is to create chimera animals that can grow organs to order. "Embryogenesis happens every day and the embryo comes out perfect 99% of the time," says Izpisua Belmonte. "We don't know how to do this in vitro, but an animal does it very well, so why not let nature do the heavy lifting?"

Today's plans to build a human-animal chimera may have provoked controversy, but they are nothing compared to the scandalous experiments of Ilia Ivanov, also known as the "Red Frankenstein". Hoping to prove our close evolutionary ties to other primates once and for all, Ivanov hatched a crackpot scheme to breed a human-ape hybrid.

Starting in the mid-1920s, he tried to inseminate chimps with human sperm, and even tried to transplant a woman's ovary into a chimp called Nora, but she died before she could conceive.

When all else failed, he gathered five Soviet women who were willing to carry the hybrid. However, the prospective father &ndash called Tarzan &ndash died of a brain haemorrhage before he could carry out his plan. Ivanov was eventually arrested and exiled to Kazakhstan in 1930 for supporting the "international bourgeoisie" a crime that had nothing to do with his grotesque experiments.

Unlike the "geep", which showed a mosaic of tissue across its body, the foreign tissue in these chimeras would be limited to a specific organ. By manipulating certain genes, the researchers hope they could knock out the target organ in the host, creating a void for the human cells to colonise and grow to the required size and shape. "The animal is an incubator," says Pablo Juan Ross at the University of California-Davis, who is also investigating the possibility.

We already know that it is theoretically possible. In 2010 Hiromitsu Nakauchi of Stanford University School of Medicine and his colleagues created a rat pancreas in a mouse body using a similar technique. Pigs are currently the preferred host, as they are anatomically remarkably similar to humans.

If it succeeds, the strategy would solve many of the problems with organ donation today.

"The average waiting time for a kidney is three years," explains Ross. In contrast, a custom-made organ grown in a pig would be ready in as little as five months. "That's another advantage of using pigs. They grow very quickly."

In 2015, the US National Institutes of Health announced a moratorium on funding for human-animal chimera

Beyond transplantation, a human-animal chimera could also transform the way we hunt for drugs.

Currently, many new treatments may appear to be effective in animal trials, but have unexpected effects in humans. "All that money and time gets lost," says Izpisua Belmonte.

Consider a new drug for liver disease, say. "If we were able to put human cells inside a pig's liver, then within the first year of developing the compound, we could see if it was toxic for humans," he says.

Rossant agrees that the approach has great potential, although these are the first steps on a very long road. "I have to admire their bravery in taking this on," she says. "It's doable but I must say there are very serious challenges."

Many of these difficulties are technical.

The evolutionary gap between humans and pigs is far greater than the distance between a rat and a mouse, and scientists know from experience that this makes it harder for the donor cells to take root. "You need to create the conditions so that the human cells can survive and thrive," says Izpisua Belmonte. This will involve finding the pristine source of human stem cells capable of transforming into any tissue, and perhaps genetically modifying the host to make it more hospitable.

It would be truly horrific to create a human mind trapped in an animal's body

But it is the ethical concerns that have so far stalled research. In 2015, the US National Institutes of Health announced a moratorium on funding for human-animal chimera. It has since announced plans to lift that ban, provided that each experiment undergoes an extra review before funding is approved. In the meantime, Izpisua Belmonte has been offered a $2.5m (£2m) grant on the condition that he uses monkey, rather than human, stem cells to create the chimera.

A particularly emotive concern is that the stem cells will reach the pig's brain, creating an animal that shares some of our behaviours and abilities. "I do think that has to be something that is taken into account and discussed extensively," says Rossant. After all, she found that her chimeras shared the temperaments of both species. It would be truly horrific to create a human mind trapped in an animal's body, a nightmare fit for Wells.

The researchers point to some possible precautions. "By injecting the cells in a particular stage of embryo development, we might be able to avoid that happening," says Izpisua Belmonte. Another option may be to program the stem cells with "suicide genes" that would cause them to self-destruct in certain conditions, to prevent them from embedding in neural tissue.

Even so, these solutions have not convinced Stuart Newman, a cell biologist at New York Medical College, US. He says he has been worried about the direction of this research ever since the creation of the geep in the 1980s. His concern is not so much about the plans today, but a future where the chimera steadily take on more human characteristics.

"These things become more interesting, scientifically and medically, the more human they are," says Newman. "So you might say now that 'I would never make something mostly human', but there is an impulse to do it. There's a kind of momentum to the whole enterprise that makes you want to go further and further."

How we talk about humans during this debate may inadvertently change how we look at ourselves

Suppose that scientists created a chimera to study a new treatment for Alzheimer's. A team of researchers may start out with permission to create a chimera that has a 20% human brain, say, only to decide that 30% or 40% would be necessary to properly understand the effects of a new drug. Scientific funding bodies often require more and more ambitious targets, Newman says. "It's not that people are aspiring to create abominations&hellip but things just keep going, there's no natural stopping point."

Just as importantly, he thinks that it will numb our sense of our own humanity. "There's the transformation of our culture that allows us to cross these boundaries. It plays on the idea of the human as just another material object," he says. For instance, if human chimera exist, we may not be so worried about manipulating our own genes to create designer babies.

Newman is not alone in these views.

John Evans, a sociologist at the University of California San Diego, US, points out that the very discussion of human-animal chimera focusses on their cognitive capacities.

For instance, we might decide that it is okay to treat them in one way as long as they lack human rationality or language, but that train of logic could lead us down a slippery slope when considering other people within our own species. "If the public thinks that a human is a compilation of capacities, those existing humans with fewer of these valued capacities will be considered to be of lesser value," Evans writes.

Our gut reactions should not shape the moral discussion

For his part, Izpisua Belmonte thinks that many of these concerns &ndash particularly the more sensational headlines &ndash are premature. "The media and the regulators think that we are going to get important human organs growing inside a pig tomorrow," he says. "That's science fiction. We are at the earliest stage."

And as an editorial in the journal Nature argued, perhaps our gut reactions should not shape the moral discussion. The idea of a chimera may be disgusting to some, but the suffering of people with untreatable illnesses is equally horrendous. Our decisions need to be based on more than just our initial reactions.

Whatever conclusions we reach, we need to be aware that the repercussions could stretch far beyond the science at hand. "How we talk about humans during this debate may inadvertently change how we look at ourselves," writes Evans.

The question of what defines our humanity was, after all, at the heart of Wells' classic novel. Once Pendrick has escaped the island of Doctor Moreau, he returns to a life of solitude in the English countryside, preferring to spend the lonely nights watching the heavens.

Having witnessed the boundary between species broken so violently, he cannot meet another human being without seeing the beast inside us all. "It seemed that I too was not a reasonable creature, but only an animal tormented with some strange disorder in its brain which sent it to wander alone, like a sheep stricken with gid."

David Robson is BBC Future&rsquos feature writer. He is @d_a_robson on Twitter.

75 Animal Facts That Will Change the Way You View the Animal Kingdom

Impress your friends with mind-blowing trivia about dolphins, koalas, bats, and more.


With an estimated 7.77 million species of animals on the planet, the animal kingdom is an undeniably diverse place. But while the breadth of earthly biodiversity may be well known, the incredible things our animal counterparts can do are often hidden to humans. From furry creatures you never realized kissed to those who enjoy getting tipsy, these amazing animal facts are sure to wow even the biggest animal lovers out there.


Koalas might not seem to have a lot in common with us, but if you were to take a closer look at their hands, you'd see that they have fingerprints that are just like humans'. In fact, they're so similar when it comes to the distinctive loops and arches, that in Australia, "police feared that criminal investigations may have been hampered by koala prints," according to Ripley's Believe It or Not. Any koalas who want to commit crimes would be wise to do so wearing gloves.


Parrots may be associated with pirates, but it turns out African grey parrots are nothing like the infamously greedy, treasure-seeking criminals. Instead, researchers have discovered that the colorful birds will "voluntarily help each other obtain food rewards" and perform "selfless" acts, according to a 2020 study published in Current Biology. Study co-author Auguste von Bayern noted, "African grey parrots were intrinsically motivated to help others, even if the other individual was not their friend, so they behaved very 'prosocially.'"


Prairie dogs are quirky creatures for a number of reasons: They're giant rodents, they dig massive interconnected underground homes, and they kiss. While they're actually touching their front teeth in order to identify each other when they seem to be sweetly sharing a smooch, the BBC explains that scientists believe prairie dogs "'kiss and cuddle' more when they are being watched by zoo visitors," because they "appeared to enjoy the attention."


Crabs may be able to intimidate other creatures with their claws, but if that's not enough, ghost crabs will growl at their enemies like a dog. However, unlike our canine friends, crabs make these fearsome noises using teeth located in their stomachs. "There are three main teeth—a medial tooth and two lateral teeth—that are essentially elongated, hard (calcified) structures. They are part of the gastric mill apparatus in the stomach, where they rub against each other to grind up food," Jennifer Taylor, from the University of California, San Diego, told Newsweek. She and her colleagues were able to nail down the source of the noise after noticing that "the crabs [were] 'growling' at" them.


You might think that boxers have the most impressive jabs, hooks, and uppercuts on the planet, but it's the mantis shrimp that boasts the world's fastest punch. Traveling at about 50 mph, when a shrimp punches, its little fist of fury (which, of course, isn't a fist at all) is "accelerating faster than a .22-caliber bullet," according to Science. National Geographic shared the tale of one such small smasher, explaining that "in April 1998, an aggressive creature named Tyson smashed through the quarter-inch-thick glass wall of his cell. He was soon subdued by nervous attendants and moved to a more secure facility in Great Yarmouth. Unlike his heavyweight namesake [former professional boxer Mike Tyson], Tyson was only four inches long. But scientists have recently found that Tyson, like all his kin, can throw one of the fastest and most powerful punches in nature."


While male lions attract their fair share of attention thanks to their impressive manes, it's the female lions who do the bulk of the work when it comes to feeding their families. "Lionesses, not male lions, do the majority of hunting for their pride," according to CBS News. "Lionesses hunt around 90 percent of the time, while the males protect their pride."


Narwhals are unlike most other whales because they have what appears to be a giant tusk. But that's not actually a tusk at all—what you're seeing is a tooth. Harvard University's Martin Nweeia told the BBC that the "tooth is almost like a piece of skin in the sense that it has all these sensory nerve endings," adding that it's "essentially built inside out."


Dogs are well known for being man's best friend, and it turns out that's a relationship that goes back longer than you might expect. According to Guinness World Records, the oldest known breed of domesticated dog goes all the way back to 329 BC. "Saluki dogs were revered in ancient Egypt, being kept as royal pets and being mummified after death," they note. "There are carvings found in Sumer (present-day southern Iraq) which represent a dog, closely resembling a saluki, which date back to 7000 BC."

Cats have also been hanging around humans for thousands of years. Guinness World Records reports that we've been domesticating cats for 9,500 years. Proof of this came in 2004 when the "bones of a cat were discovered in the neolithic village of Shillourokambos on Cyprus. The position of the cat in the ground was next to the bones of a human, whose similar state of preservation strongly suggests they were buried together."


Puffins surely have enough to be proud of with their beautiful beaks, but the seabirds also happen to be quite clever. According to a 2019 study published in Proceedings of the National Academy of Sciences (PNAS), Atlantic puffins in both Wales and Iceland were observed "spontaneously using a small wooden stick to scratch their bodies." Indeed, in a video shared by Science, a little puffin can be seen picking up a tiny twig before using it to scratch an itchy spot on its belly.


"Most humans (say 70 percent to 95 percent) are right-handed, a minority (say 5 percent to 30 percent) are left-handed," according to Scientific American. And the same holds true for bottlenose dolphins. In fact, the savvy swimmers are even more right-handed than we are. A team led by Florida's Dolphin Communication Project took a look at the feeding behavior of bottlenose dolphins and found that the animals were turning to their left side 99.44 percent of the time, which "actually suggests a right-side bias," according to IFL Science. "It places the dolphin's right side and right eye close to the ocean floor as it hunts."

If you're ever in the area of "the Broadway medians at 63rd and 76th streets" in New York City, keep an eye on the ground for crawling critters and you might spot something rare. That's where the "ManhattAnt" can be found, an ant that only lives in the one small area of the city. "It's a relative of the cornfield ant, and it looks like it's from Europe, but we can't match it up with any of the European species," Rob Dunn, a biology professor at North Carolina State University, told the New York Post. Dunn and his team discovered the isolated ant variety in 2012.


Cows have to deal with pesky flies that are beyond annoying for the docile creatures. Luckily, farmers can now protect their animals by painting them with zebra-like stripes. According to a 2019 study published in PLOS One, "the numbers of biting flies on Japanese Black cows painted with black-and-white stripes were significantly lower than those on non-painted cows and cows painted only with black stripes." IFL Science suggests this might work because "the stripes may cause a kind of motion camouflage targeted at the insects' vision, confusing them much in the way that optical illusions … confuse us."


Monkeys are undeniably cute. They can also be pretty darn gross. Capuchin monkeys, for example, urinate on their hands and feet when they're feeling "randy." "We think the alpha males might use urine-washing to convey warm, fuzzy feelings to females, that their solicitation is working and that there's no need to run away," primatologist Kimran Miller told NBC News. "Or they could be doing it because they're excited." Either way, ew!


People who come from different areas around the world tend to speak with inflections, fluctuations, and patterns that are specific to their home regions. Apparently, the same can be said for whales. Researchers from Dalhousie University in Canada and the University of St. Andrews in the UK have found evidence that seems to show whales in the Caribbean have a different "accent" than whales in other oceans.


In Nanning, the capital of China's Guangxi province, a man named Pang Cong has a rather remarkable animal living on his farm: a 1,102-pound pig. That's roughly the same size as a full-grown adult male polar bear. According to Bloomberg, massive swine of that size "can sell for more than 10,000 yuan ($1,399), over three times higher than the average monthly disposable income" in the area.

National Geographic via YouTube

Sharks boast some enviable—and terrifying—features, like their sleek design and razor-sharp teeth. And while glow-in-the-dark sharks sound like something you'd see in a sci-fi film, they're totally real, as noted in a 2019 study published in iScience. Researchers were already aware that some shark species produce a glow that only other sharks can see, but now scientists have discovered that "previously unknown small-molecule metabolites are the cause of the green glow," according to CNN. This glow "helps sharks identify each other and even fight against infection on a microbial level."


While it's not a secret that snails have shells, you probably didn't know that some actually have hairy shells. These hairs are rather handy to have, as they help a snail stick to wet surfaces like leaves.


Cowbirds lay their eggs in other bird species' nests, which means that the little ones eventually need to reconnect with their own kind when the time is right. And when that time comes, the young birds have a trick for figuring out who to reach out to. "Juvenile cowbirds readily recognize and affiliate with other cowbirds. That's because they have a secret handshake or password," according to Science Daily. To put it more simply, they use "a specific chatter call" to beckon each other.


If you have best friends who have been around since you were a child, then you have something in common with Tasmanian devils. Research has shown that Tasmanian devils form bonds when they're young that last for the rest of their lives. As Zoos Victoria's Marissa Parrott told IFL Science, "In the wild, when baby devils leave their mums, we believe they all socialize together." As the website notes, "young devils have their own dens," "engage in friendly sleep-overs," and when given the chance, they prefer "to share with their … original friends."


Those who find themselves in the presence of a grizzly bear will surely want to stay out of reach of this animal's super sharp claws. But they'll certainly also want to keep out of the grizzly's mouth, because these creatures "have a bite-force of over 8,000,000 pascals," according to National Geographic. That means grizzly bears can literally crush a bowling ball between their jaws. Yikes!


You might think that a whale's massive size is the only edge they'd need when it comes to hunting in the open waters. But humpback whales actually team up to use a "bubble-net" technique in order to catch their prey. "Sometimes, the whales will swim in an upward spiral and blow bubbles underwater, creating a circular 'net' of bubbles that makes it harder for fish to escape," Science News reports.


When you hear a housefly buzzing around your home, you might be annoyed by the persistent sound. However, the next time it happens, try to soothe yourself by noting that the airborne pest is actually buzzing in an F key. How melodious!


If you already thought that eels were kind of creepy, then this fact isn't going to make you feel any better about them. Moray eels have what's called pharyngeal jaws, which are a second pair of "Alien-style" jaws that are located in the throat and emerge to grasp prey before pulling the unfortunate meal down into the eel's gullet.

Over in New Zealand, surfers have noticed the same thing that those who ride the waves in California have witnessed: ducks can surf. The birds do so in order to catch food or simply to move through the water quickly. Sports reporter Francis Malley spotted a female duck and her babies catching a wave and told the New Zealand Herald, "The mother was surfing on her belly on the whitewash. I've never surfed with ducks before so this was a first."


They may be cute, but their bite can kill. According to Popular Science, these adorable animals secrete toxins from a gland in the crook of their inner arms. Their bites have caused anaphylactic shock and even death in humans. Better watch out!


You might think of pigeons as… not that smart. But it turns out, they're actually quite intelligent. In fact, one 2011 study published in the journal Science found that the birds are capable of doing math at the same level as monkeys. During the study, the pigeons were asked to compare nine images, each containing a different number of objects. The researchers found that the birds were able to rank the images in order of how many objects they contained. Put simply, they learned that the birds could count!


Cows may benefit from artificial stripes, but zebras have the real deal. One 2012 report published in the Journal of Experimental Biology suggests that zebras' black and white stripes may be an evolutionary feature to fend off harmful horsefly bites. "A zebra-striped horse model attracts far fewer horseflies than either homogeneous black, brown, grey or white equivalents," the researchers wrote.


Humans aren't the only animals who enjoy a drink or two. A 2015 study published in the journal Royal Society Open Science reveals that chimpanzees in Guinea had a fondness for imbibing fermented palm sap and getting tipsy in the process.

Jiri Prochazka / Shutterstock

While many scientists believe that tool use among dolphins is a relatively new phenomenon, a 2017 study published in Biology Letters suggests that otters may have been using tools for millions of years. Sea otters frequently use rocks to break open well-armored prey, such as snails.


Why tolerate the cold when you could just freeze yourself solid? According to Kenneth Storey, a professor at Carleton University in Ottawa, frogs undergo repeated freeze-thaw cycles. "We have false springs here all the time where it gets really warm and all the snow melts and then suddenly—bam—the wind comes from the north and it's back down to minus 10, minus 15 [Celsius], and they're fine," Storey told National Geographic.


Male horses have 40 to 42 permanent teeth, while females have just 36 to 40. According to the VCA Animal Hospital, the original purpose of these extra teeth was as fighting weaponry.


If you thought your cat was sleepy, just wait until you hear about koalas. According to the Australian Koala Foundation, these cuties sleep between 18 and 22 hours a day. The koalas' diets require a lot of energy to digest, which is why they've got to nap so much.


No, it's not because they're so professional—it's a modernized form of "busyness," the word originally used to describe a group of these weasel-related mammals.


And yes, they are called arms, not tentacles. According to the Library of Congress, the animals can taste and grab with the suckers on their arms. Even more impressive? Octopuses are capable of moving at speeds of up to 25 miles per hour.


You already know that dolphins are smart. But did you know that they even have their own names? One 2013 study published in PNAS found that bottlenose dolphins develop specific whistles for one another.


Reindeers have beautiful baby blues—but only in the winter! According to the Biotechnology and Biological Sciences Research Council, "the eyes of Arctic reindeer change color through the seasons from gold to blue, adapting to extreme changes of light levels in their environment." The change in color impacts how light is reflected through the animals' retina, and improves their vision.


Scientists believe that it's so they don't get sunburns while they eat. The animals' tongues are also around 20 inches long.


In busy waters, manatees will nudge alligators to get in front, and alligators generally oblige.


Everything about life is slow for these sleepy mammals. Most sloths will only have a bowel movement once a week, and it can take them up to 30 days to completely digest a single leaf. For comparison, it takes the average human 12 to 48 hours to ingest, digest, and eliminate waste from food.


You probably know that cats love to talk to their humans. But did you know you're unlikely to see your feline friend interact the same way with another cat? That's because other than kittens meowing at their mothers, cats don't meow at other cats.


Elephant calves will suck their trunks to comfort themselves. The babies do it for the same reason humans do (it mimics the action of suckling their mothers).


According to Bat Conservation International, bats give birth to babies—known as pups—that can weigh as much as one-third of the mother's weight. If that doesn't sound like a lot, imagine a person giving birth to a baby that weighed 40 pounds.


Not all creatures head to warmer climates when it gets cold out, and that means they need to learn to survive in chilly conditions. Painted turtles need to adapt to frozen ponds, which restrict their access to the air above the water. They do that by breathing through their butts—specifically, the all-purpose orifice called the cloaca. Thanks to a process called cloacal respiration, the turtles are able to get oxygen directly from the water around them.


While you may think that Fido has the same dinnertime experience as you do, he's actually got a much different taste bud arrangement. Humans have about 9,000 taste buds, while dogs have only around 1,700. And while they can identify the same four taste sensations as people, dogs are not fond of salt.


They're thought to have up to one million hairs per square inch. Their fur consists of two layers and is designed to trap a layer of air next to their skin so their skin doesn't get wet.


According to a 2018 study published in Copeia, alligators often haven't hit their full size until 33.


Their legislative powers, however, are still up for debate.


Snow leopards have less-developed vocal cords than their fellow large cats, meaning that they can't roar, but make a purr-like sound called a chuff instead. For a 2010 study published in the Biological Journal of the Linnean Society, scientists researched why some cats have a higher-pitched meow than others. They found that it's not size that determines a kitty's call, but habitat.


The salamanders are the only vertebrates that can replace their skin, limbs, tail, jaws, and spines at any age. On the flip side, humans can regenerate lost limb buds as embryos and fingertips as young children.


The Incredible History of Stuffed Animals

Just about every one out there can think of a favorite stuffed animal that they have or that they had at one time. These soft toys are often very special to use and can help us to get through the rough times that come our way in life. Since we see stuffed animals all over the place, it is easy to assume they have always been available. Learning about the history of stuffed animals though can help you to appreciate them more.

It is believed they actually originated centuries ago in the Egyptian culture. While the remains of the actual stuffed animals haven't been found, paintings of them around the tombs of the Egyptians have given researchers the impression that they did have them. In other cultures it is believed they were used for ceremonies to take the place of real animals.

The first stuffed animals were introduced in the 1830's. There weren't well made like today though in factories with various types of stuffing. Instead these were homemade. The materials used were cloth and straw. As time progressed new materials were used. How many of you remember sock puppets as toys? Most children today don't but older generations loved to play with them.

It may surprise you to learn that stuffed animals actually came from the idea of stuffing real animals that had been killed. That is still a process that hunters engage in today as a way to preserve the beauty of those animals. It is also a way to display them as a trophy. However, that process can be both time consuming and expensive.

The idea of stuffed animals as we know them today took place in 1880. These were the first commercialized types. They were manufactured in Germany. There are now brand names out there made all over the world.

As materials including cotton and various types of synthetic fibers were introduced, they became the main types of items used to stuff these delightful toys. They could be produced quickly and very inexpensively. The idea of using beans to stuff them also added appeal down the road in this market.

In the United States the attention for stuffed animals occurred when President Roosevelt was shown with a picture of a cuddly icon. A manufacturer approached the President to ask to use his name with the production of them in 1902. Today there are thousands of different types including the teddy bear out there for you to choose from.

Even though kids today seem to be more interested in electronic gadgets than using their imaginations to play, stuffed animals are still hot selling items. You will find many classics out there including Raggedy Anne and Andy, teddy bears, and Disney characters. Some of the older stuffed animals are considered collector's items and are worth a great deal of money if they are in good shape. You may have some of them around your home or packed away that are more valuable than you ever imagined.

Siau Island Tarsier

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