It's actually really difficult to accurately determine what the world's rarest animals are, especially as natural habitats continue to disappear.
It’s surprisingly difficult to determine the rarest species — mainly because animals don’t really participate in censuses. Some animals are so rare that they might already be extinct and we just don’t know it yet. Others are extinct in the wild and can only be found in captivity.
But from what we know, the four creatures featured below are as rare as prime rib.
Pygmy Three-toed Sloth
The sloth is already one of the most adorable creatures on Earth, but to be honest, it’s not really much of a survivor. You put it in any kind of dangerous situation and it is likely to perform poorly. Therefore, it shouldn’t be that surprising to find out that the pygmy three-toed sloth is critically endangered.
Right off the bat, we weren’t really expecting the species to be in abundance. It is endemic to a small island near Panama called Escudo de Veraguas so there’s not a lot of room to thrive. Even so, we were expecting the population numbers to be somewhere in the mid hundreds.
The latest study showed that there are only 79 still poking around. It does have one advantage in that the island isn’t inhabited by humans, but poaching is still a problem since the sloth isn’t exactly what you would call a master of escape.
More popularly known as the Javan rhino after the island where it is found, the Sunda rhinoceros is considered to be one of the rarest animal species in the world. Fewer than 100 examples are thought to exist in the world. Even though it was once spread all over Southeast Asia, the Sunda rhino is now confined to the Ujung Kulon National Park.
Unsurprisingly, we are the ones most responsible for the rhino’s declining numbers. It was always hunted for its horn, which is pretty weird since one of the definitive traits of the Sunda rhino is having a smaller horn than other species. Although it is closely related to the Indian rhino, it is more comparable in size to the black rhino.
Although it has been a protected species for a while now, other factors such as national instabilities (read: wars) have kept the population from recovering.
Earth’s Rarest Animals: The Metallic Tarantula
There are many people who would recoil at the very idea of making any kind of effort to save a spider. Still, spiders get a bad rap and they aren’t as vicious as most of us think. Take, for example, the metallic tarantula aka the Poecilotheria metallica aka the Gooty tarantula (named after the town where it was discovered).
The spider is characterized by a brilliant blue metallic color that covers most of its body. It is not very dangerous unless you are an insect (and since you’re reading this on a computer, that seems unlikely). However it does have venom and it would definitely hurt if it found its way into your body, but most of the bites are “dry”, meaning that no venom is actually injected.
The main problem the metallic tarantula faces is the loss of its habitat due to deforestation. However, it is also quite a valuable commodity—a single tarantula can go for hundreds of dollars—in the pet trade so poaching is an issue as well.
It’s possible that you could literally count all the remaining Hainan gibbons — a really weird pet — on your hands and feet. One 2003 study found only 15 of them left, and a 2004 study found between 12 and 19. The latest count found 22 gibbons separated into two families, with four adult loners who split from their groups and went off to start their own families.
Just to give you an idea of how serious their decline was, about six decades ago over 2,000 gibbons were found on Hainan Island in China. A hawk might snatch up a young gibbon every now and then, but mostly it’s us doing the damage.
Like so many of the other animals featured here, gibbons’ declining numbers stem from habitat loss. It doesn’t help that their bones are prized in traditional medicine, either.