"The ugliest animal in the world"? No, it's a great miracle of evolution

In the north of my country, there is a unique term: "di le pai (pǎi) zi" (Calendar Niang: Teacher Yu Qian once used it to describe Li Jing's cousin). I believe that most young people in cities don't know what it is. But if you ask its official Chinese name, I believe you must have heard of it, which is mole. And the word "mole", including me, many people will read it as yàn, but the correct pronunciation is yǎn.

In the impression of a city kid born in the 1980s like me, the image of the mole mostly comes from the Czechoslovak cartoon "The Story of the Mole". A black little guy, holding a small shovel in his hand, digs a tunnel under the farmer's garden, and piles of dirt are piled up on the ground, making the farmer so angry that he jumps up and down and curses.

The busy little mole. Image: Animation "The Mole's Story"

The prototype of the protagonist in the story of the mole, the "little mole", is the common European mole (Talpa europaea). In North America, there is a very strange mole, which not only has special skills, but also has a special appearance. It is a well-deserved "tentacle monster". This is the star-nosed mole (Condylura cristata) that we are going to introduce to you today.

Wearing a tycoon coat

Although both moles and mice have the word "mouse" in their names, they are still very different: moles belong to the class Mammalia, the order Laurasia, the order Shrews, and the family Moles, while common mice belong to the order Primates, the order Rodentia. The star-nosed mole is the only species in the genus Star-nosed Mole.

The star-nosed mole is a strange looking creature. Photo: gordonramsaysubmissions / Flickr

You may have heard that moles belong to the "Insectivora", so what about this "Shrewriformes"? In the old taxonomic system, moles and some other small animals that like to eat insects were all classified under the Insectivora. But later, with the development of molecular taxonomy, it was found that although these animals are similar in shape and have the habit of eating insects, their relationship is relatively distant. Therefore, in the new taxonomic system, the Insectivora is divided into three: Shrewriformes, including moles and shrews that look like mice; Erinaceiformes, including hedgehogs; Afrocephalus, including some small insectivorous animals in Africa, some of which look like moles and some like hedgehogs. Interestingly, compared with the other two orders, Afrocephalus is more closely related to elephants.

The star-nosed mole is not big, with a body length of about 20 cm and a weight of about 50 grams, which is not much bigger than a house mouse. The star-nosed mole is short and thick, and its body structure is very suitable for living in underground tunnels. Its fur is also very smooth, so that resistance can be minimized, and the material of this dark brown coat is also very high-end. In Andersen's "Thumbelina", the mole wears "a black velvet robe that the queen doesn't have" and is a big local tyrant. The European cousin of the star-nosed mole, the European mole, was once hunted in large numbers and made into fur coats for the nobles to wear.

Tentacle-like face

The name of the star-nosed mole comes from its special nose with 22 "tentacles", which has a very Cthulhu Mythos feel. This set of tentacles is called a star-shaped appendage. When I first saw this thing, I naturally thought it was an olfactory organ that could add a buff to my nose.

The devil's sniff. Image: natural geographic

But later I found out that I was wrong. This wonderful tentacle structure is actually a tactile organ. The star-nosed mole uses its star-shaped appendages to touch the surrounding environment to distinguish the surrounding objects, just like we humans use our eyes to observe the world. There are about 25,000 tactile receptors called "Aimer's organs" on these tentacles. These receptors are distributed under the epidermis and arranged in a honeycomb pattern. There are more than 100,000 surface nerve endings on the entire appendage. What kind of concept is this? We humans generally have 17,000 nerve endings on the entire palm of our hands, while the surface area of ​​the star-shaped appendage of the star-nosed mole is only about 2 centimeters, which is similar to the area of ​​the tip of an adult male's thumb. In other words, the star-nosed mole concentrates the equivalent of 6 hands of nerve endings on an area as small as a fingertip. Its tactile sensitivity can be imagined.

The star-nosed mole's nose can be used as a walking stick to find its way. Image: Natural Geographic

The star-nosed mole mainly lives in the shallow soil of wetlands. Its food mainly consists of various worms and mollusks in the soil. It occasionally preys on insects or other small invertebrates in wetlands. The star-nosed mole's eyes have almost disappeared, and it seems that it can't see anything except light. When it moves, it will use its "tentacles" to quickly touch the walls of the tunnel at a speed of up to 12 times per second, gather the information obtained into the brain, and then draw a "map" in the brain. When the star-nosed mole shuttles through the tunnel, if it encounters changes in the surrounding environment, it will push its tentacles over, touch repeatedly, and update the map in its brain. If it encounters food, such as fat earthworms, the star-nosed mole will react within a few tenths of a second, and pounce on the prey with lightning speed to eat it.

Like most shrews, the star-nosed mole has an extremely fast metabolism and must eat constantly to avoid starving to death. The food it eats every day is almost 70% of its body weight, and at certain times, the amount of food it eats even exceeds its body weight.

Being ugly is also a miracle of nature

Unlike other moles, the star-nosed mole is well adapted to aquatic life. It is very good at swimming and can dive underwater to prey on a variety of small aquatic animals. The most amazing thing is that it can smell underwater with its nose.

American researchers found that when star-nosed moles dive, they constantly spit out bubbles from their nostrils and then quickly suck them back in, with a frequency of up to 10 times per second, which is very similar to the way mice or rabbits smell the odor in the air. The researchers then made a water-filled "maze" with two forks to choose from. When earthworms were placed on one side, the star-nosed mole would choose the path with earthworms three out of four times, and when nothing was placed, the probability of the star-nosed mole choosing the two paths was almost half and half. After the bubbles come into contact with objects in the water, the odor molecules will diffuse into them and then be sucked in by the star-nosed mole, so that the star-nosed mole can smell the odor in the water.

The star-nosed mole's nose blows bubbles into the water and then sucks them back in. Image: National Science Foundation / youtube

When I was writing this article, I randomly searched for star-nosed moles on a well-known search engine in China, and found that many of the entries that popped up were selections of the world's ugliest animals, including star-nosed moles. In my opinion, although the little tentacle monster looks strange, it is far from being "ugly". Moreover, we cannot use our own aesthetics to demand an animal. It is absolutely wrong to use "looking at the face" to evaluate the value of an animal's existence. For example, in Madagascar, there is a primitive primate with a weird appearance - the finger monkey (Daubentonia madagascariensis). Because of its indescribable appearance and nocturnal habits, it is considered by the locals to be the incarnation of the devil and is hunted. The finger monkey is just a weak little animal that eats insects and is harmless to humans. It is really unfair to be killed just because its appearance does not meet our aesthetic standards.

Lorenz, the founder of animal behavior, once said that he hated to see people laugh at chameleons, pufferfish, anteaters and other animals with strange and funny appearances, because the strange appearances are the results of evolution and the great mystery of life. In fact, the reason why I chose to write popular science is to share the various magical things in this world with more people. If you understand why the star-nosed mole has such a nose, you will also respect it.