From 0 to 6: how many fingers do different animals have? Interesting mutations and forms (19 photos)

Five fingers on the limbs is the norm for us. But other animals have different norms. Some may have six fingers, while others may have none at all. Let's go through the entire range from minimum to maximum!





0 fingers

Well, it's clear that snakes don't have fingers, but they also don't have limbs, so these reptiles don't count. But you can find real fingerless animals among... whales! Oddly enough, whales still have legs, albeit in a greatly degraded state. All that remains of the limbs are small (relative to the size of whales) femurs. But the feet and, accordingly, the toes have been gone for tens of millions of years. Over time, the remains of their legs will also disappear, but for now whales are the only vertebrates with legs, but without toes!



The pelvic and leg bones of whales are so reduced that they hang directly in the muscles and are not connected to the spine in any way. Therefore, museum workers had to attach them with plastic things!

1 finger

As surprising as it may sound after the previous paragraph, it seems that there are no animals on Earth with a single finger on a limb. Horses could lay claim to this title - when walking, they really do rely on one toe with a powerful hoof. But in fact, horses have a full set of five toes.





Some horses do grow an extra toe. It looks like the animal walks in heels all the time.

Of course, four of the five toes are poorly developed and do not perform any functions. Moreover, the processes have become so invisible that their full set on the limbs of horses was discovered only in 2018. Before that, it was believed that their feet were three-toed. And while there are microfingers, horses cannot be called single-toed.



Evolution of horse fingers. Most likely, in the near future, degraded fingers will disappear completely from horses.

2 fingers

Reducing the number of processes on the limbs to just two is a very radical solution from a mechanical point of view. Therefore, it is only suitable for those who need unusual ways of moving. For example, ostriches. The reduced number of fingers slightly reduced stability, but increased maximum speed. The smaller the contact area, the easier it is to push off the ground and accelerate. That's why ostriches are able to run at a speed of 70 km/ h!



It's like a finger is missing, don't you think?

In addition to them, two-toed sloths have paws with two fingers. Two fingers with powerful claws evenly distribute the load and do not take up much space. Therefore, the sloth can hang in one place for hours.



A two-toed micro sloth crawls along your internet cable.

3 fingers

We see owners of three-fingered limbs almost every day. Who are they? Birds! Almost all birds have three fingers of uncertain origin in their wings. Why uncertain? Because paleontologists and anatomists claim that birds have preserved fingers 1, 2 and 3. And embryologists say that they have 2, 3 and 4.



A bird's front leg without feathers, muscles and other unnecessary tinsel.

There are also birds who have equalized the number of fingers on their front and back limbs. Cassowaries, rheas and emus are among the few birds with a tridactyl type of leg structure. All three toes point forward. Why this happened is an open question. The vast majority of birds use the fourth toe to maintain balance.



The cassowary's third toe is a cold weapon. The claw on it reaches a length of 12 cm.

You can literally count the three-toed mammals on the fingers of one hand. More or less well-known animals with this structure are odd-toed ungulates. Rhinoceroses have three toes on all limbs; tapirs have three processes only on their hind legs. There are also three-toed sloths and three-toed jerboas. Both animals are narrow specialists and are considered an exception to the rules of the mammal world.



I wonder if they would get a discount on manicures?

4 fingers

But four fingers in the wild won't surprise anyone. If you don't need to grab anything, you can get rid of one finger without much loss. That's why four-fingered animals are found in almost every vertebrate order. Even colobus monkeys managed to abandon their thumb and not go extinct. But they are primates, just like us. They are supposed to grab onto branches!



Your face when you accidentally removed a finger during the process of evolution.

For birds, four-fingered feet are an interspecies standard. Three fingers point forward, and one points back. This structure helps maintain balance. In addition, this scheme is time-tested. Four-fingered feet were already common among dinosaurs, birds simply did not change what already works great.



A jacana chick proudly walks on its four-fingered feet.

5 fingers

If four fingers are the standard for birds, then five is already the standard for the vast majority of all vertebrates. The very first amphibian to crawl out onto land, small and awkward, had five fingers on all its limbs. And all the land vertebrates of the planet have descended from it. Frogs, lizards, bears, dogs, cats, rodents, primates, pinnipeds — we can give most animals on the planet a five.



Me and Sanya (five-fingered).

It is interesting that some animals refuse an extra finger if they do not need it. So, all representatives of the feline family have five-fingered front paws and four-fingered back paws.



Epic quintuplet of two bros.

6 fingers

Now this is not normal at all. Polydactyly is a genetic mutation or developmental defect in the early stages of fetal development. In most cases, the extra finger is a poorly formed lump of skin, bone, and muscle. Very rarely is it fully functional. Usually, animals with polydactyly lose to their normal-fingered relatives. But in cats and dogs, polydactyly is a relatively common occurrence. All thanks to human intervention, which does not allow evolution to remove multi-fingered ones through natural selection.



— How many fingers do you see? — 12... — Correct!



1 blow – 6 wounds. Scary...

True, there are two species of truly six-fingered animals on Earth: the panda and the aye-aye lemur. They did not fix polydactyly in their genes, but formed a sixth finger from elongated hand bones, tied with additional ligaments.



Hey, human, give me six!



Comparison of the panda's paw and the brown bear's.

These pseudo-fingers are not as flexible as the regular ones. But they are enough to grab bamboo and branches with greater strength and dexterity! In fact, the thumb performs the same function in many animals. But, apparently, it is easier to create a new process than to move an existing bone to the right place.



A professor from California shows us the attachment point of the lemur's 6th finger. It is also very underdeveloped.



The Aye-Aye Lemur's hand is already creepy, and now the 6th finger is hidden...