It’s hard to find uniqueness in the world sometimes. A million people probably have the same haircut as you, or love the same movies, or have the same favorite food. The animal kingdom is no different. But for every feature or trait there will always be one thing, one creature, that was first to display it or make use. And there are some other features that are so unique that only one living thing can lay claim to them.
10. A Presumed Extinct Rodent Showed Up To Pose for Photos Then Vanished Again
Colombia’s red-crested tree rat is pretty cute for a jungle rat, not that many people can confirm that in real life. The animal was first discovered in 1898 and it wasn’t until 1913 before anyone saw one again. That was also the last time anyone saw one for nearly an entire century.
After almost one hundred years it seemed like the rat had probably died out and it was generally believed extinct. Researchers looking for examples of the creature had not had much luck in coming up with any evidence whatsoever.
In 2011, a pair of volunteers were out photographing wildlife when a rat showed up unexpectedly and stayed in sight for two hours where they could photograph it before it vanished into the woods again. It even let them get close for detailed, close up images. No one has seen one since, either.
9. The Sea Walnut Has a Moving Anus
The sea walnut, aka the warty comb jelly, is an animal that seems to have been custom made for the immature to giggle at. A sort of jellyfish, this small, translucent and exceedingly rare creature has the only known example in nature of what scientists called a “transient anus.” It means exactly what it sounds like it means – this animal has a roaming butt hole.
As waste material builds up inside the sea walnut’s body it needs to be excreted just as it would in any other animal. But unlike the rest of us, the sea walnut has no orifice with which to do that. Instead, pressure forces the waste towards wherever. Literally anywhere on the creature’s body, and then forces it out like poking your finger through some plastic wrap. Once the waste pops out, the hole closes over and then next time it will probably pop out somewhere else.
8. A Baboon Troop in Kenya Became Peaceful and Taught it to Others
In the primate world, baboons are generally not regarded as the most chill animals. They have a reputation for aggression. And that’s exactly why a troop of the animals made international news back in the 1980s. Not for being aggressive but for how they managed to pull a complete 180 on their behavior.
A severe outbreak of tuberculosis struck one troop of baboons in Kenya. The main victims of the disease just happened to be the most aggressive males – the ones most prone to violence and aggression that we, as humans, might describe as alphas. There were other males in the troop but they were not as powerful and therefore not aggressive. So a funny thing happened when the violent ones died off. The remaining females, young baboons, and gentle, docile males just continued life as a pacifist troop.
Rather than a new aggressive leader taking control, the remaining baboons were generally kind and caring with one another. Grooming took over for violent attacks. More astonishing is that, as scientists studied the troop for another 20 years, even when the pacifist males died out and new males either grew into more dominant roles or even joined from outside troops, the behavior remained. The troop stayed generally calm, passive, and caring with its own.
Researchers agreed that the group must be able to teach this kinder way of life to outsiders as they join, though they were not sure how.
7. Sea Sponges Can Reform After Being Destroyed
A few things are true of most living things. Most of us like food and water and air, even if we pull it out of water to survive. Not many things like fire. And most of us don’t like being ground down to individual cells because that’s really uncomfortable. However, if you’re a sponge, at least you can get over it. No other organism can.
Sponges can be pulled apart right down to their individual cells and, given time, they will reassemble themselves into a single organism again, sort of like a simple version of the T-1000 from Terminator 2.
You can even check out time lapse video of sponges in labs that are passed through sieves and forced apart. Their cells will gather and recombine, forming new sponges as a result that can go on living their lives.
6. A Fish Parasite Doesn’t Require Any Oxygen at All
In that last entry we mentioned that most living organisms like oxygen. Even creatures from the sea use gills or other means to take oxygen from the water to keep themselves alive. But the parasite known as Henneguya salminicola stands alone in its utter lack of concern for oxygen. It is the only living animal scientists have discovered that cannot breathe oxygen and therefore has no need for the element.
The parasite infects salmon and trout and causes a condition called tapioca disease, which is about as gross as it sounds. The parasites form white nodules in the flesh of the fish. They are very small, only 10 cells make up one of these parasites, and they are smaller than most cells in a human body. But they have no mitochondria and therefore do not convert sugar and oxygen into energy. Scientists aren’t actually sure what powers the parasite’s cells, though they suspect they steal some energy from their hosts.
5. Mantises Are the Only Creatures with a Single Ear
In the insect world, mantises standout for being some of the coolest looking creatures on Earth, especially orchid mantises. And the penchant for female mantids to eat the heads of the males after mating, or sometimes during, is also something that captures the imagination of many people. But while that’s interesting it’s not technically unique. Many spiders consume their mates as well. But mantises do have one unique claim to fame and that’s a cyclops ear.
It was long believed that a praying mantis is deaf because it doesn’t have ears. But scientists weren’t looking in the right place. The single ear, able to hear the ultrasonic cries of bats, is located inside the mantis’ thorax, right in the middle of its chest. There’s just one of them and that seems to be all the insect needs, given its central location.
Mantis hearing is so good that, in midair, they can detect a pursuing bat and bank then dive like a fighter jet right at the ground, gaining speed as they do so, in order to avoid the predator.
4. A Species of Deep Sea Snail Makes Armor out of Iron
There are a few animals in the world that we generally consider to be armored. Turtles, armadillos, crabs, and snails tend to come to mind. But it’s not armor in the human sense, of course, just some kind of shell or carapace that’s tough and durable and offers a degree of protection. Except for maybe one species of snail. The scaly foot snail uses actual iron in the construction of their shells and they are the only animal that does so.
The snails live near thermal vents in the Indian ocean. Waters around these vents get up to 400 degrees Celsius, which is four times the temperature of boiling water. They use minerals spewed out of these vents to form shells so while some use iron sulphide others will make use of pyrite or Fool’s Gold, and gregite as well. They form their shells of this stuff and also plates that cover their soft feet.
Normal snails have two-layered shells. One is a calcium carbonate, the inner layer, and it helps dissipate heat. These iron snails have that. The next layer, or outer shell, is the tough one that helps absorb damage and protect the snail from predators.
These deep sea snails have a third layer, and that’s where the metal is used. The iron or other elements form a nanoparticle coating on the shell. If a predator tries to crush the snail. These particles help absorb the damage and also blunt the claws or teeth of the attacker. It’s so effective the military has even been studying the science of how it works in the hopes of creating new armor types.
3. One Kind of Skink Has Lime Green Insides
In order to make a character like Spock on Star Trek seem a little more alien than just a guy with pointy ears, the producers gave him green blood. In older sci-fi you’ll find few things more unusual than the color green. Little green men were a trope, after all. It’s not something we’re used to in life beyond plants and lizards on earth. But when lizards on earth go green, some go all out. Like the skink, for instance. Skinks are so green they are the only animals in the world that go green inside as well.
The inside of a certain kind of skink of the genus Prasinohaema is bright green. Bright green blood, bright green organs, even bright green bones. It’s unlike anything else you’ll find in nature. It comes from a compound called biliverdin, which is highly toxic to most life forms. Normally it’s a waste product from the breakdown of red blood cells. Humans make something similar called bilirubin. If we can’t eliminate it, it leads to jaundice and a yellow discoloration of the skin.
The compound isn’t really a defense mechanism as birds still eat the lizards. And it’s not camouflage either as not all of them are green outside. So researchers speculate, and it’s not proven at all, that maybe it protects against parasites.
2. The Pyrenean Ibex is the Only Species to go Extinct Twice
Is the Pyrenean Ibex literally the unluckiest animal in history? Maybe. Certainly there are plenty of creatures that would be in the running for that title but luck is sort of a diffuse and malleable attribute so by some standards you could definitely say nothing else has been unlucky. So how do we measure luck? In this case we’re doing so by factoring in death. The Pyrenean Ibex has died more than any other species in history because it’s the only one that has had to endure going totally extinct not once but twice.
As the name suggests, these antelope-like animals once called the Pyrenees Mountains home. Their numbers dwindled throughout the 20th century and by 1997 only one was left alive. The body of that one was discovered in the year 2000 after it had been crushed by a fallen tree. Thus the millennium started with the first extinction of the Pyrenean Ibex.
The genetic material from that last ibex had been harvested well before her death. A team of scientists set about cloning her and inserted her genetic material into the egg of a goat that had been stripped of its own. They made 57 embryos and implanted them in a different kind of ibex. Only seven of the creatures became pregnant and of those just a single one was able to give birth.
In 2003, the Pyrenean Ibex became unextinct when a brand new baby was born. The celebration was short-lived, however, as the baby had a severe respiratory condition. It survived for about 10 minutes and then the species went extinct all over again.
1. Hagfish are the Only Animals That Have Skulls But Not Spines
Hagfish enjoy a bit of infamy on the internet thanks to their unusually phallic appearance and the fact they produce copious amounts of incredibly thick slime as a defense mechanism. Numerous hagfish can turn huge swaths of ocean water into little more than a salty Jello mold to trap and potentially suffocate predators.
While those are unique features, they’re still not the most unusual thing about these creatures. Hagfish are the only animals that have a skull in their heads but no spine connected to it. Without vertebrae they can’t technically be vertebrates. They also don’t have jaws and the skeleton they do have isn’t bone, it’s cartilage.