Sloth: As long as I'm slow enough, natural enemies can't see me! When 'slowness' becomes a talent
Audit expert: Ran Hao
well-known popular science writer
Surrounded by reinforced concrete, most of our knowledge of nature comes from TV programs since childhood. Accompanied by Mr. Zhao Zhongxiang's classic opening remark: "Spring is here, everything is revived, and it's the season of animal mating...everything starts to be restless", the fantasy "animal world" once again caught our eyes.
The agile leopard was chasing the antelope, and it was really sweating for the antelope at that time; the crocodile in ambush in the water was secretly watching the zebras drinking water, waiting for an opportunity to attack, but the zebras were also very alert. Once they found any danger, Run as fast as you can. In nature, "doing the best" seems to be the most used life-saving strategy.
This strategy is definitely a housekeeping skill for animals that run fast, such as antelopes, zebras, hares, ostriches and other animals. But don't forget that there are some animals that are always "slow and half a beat". When encountering a predator, do you want to run? That is to be instantly killed. So, how do these slow-moving animals survive when they encounter natural enemies? Today, the editor will introduce to you several well-known "slow sons".
The "real" sloth
Seeing the name of the sloth, you can basically know the characteristics of this animal: they live in trees and are very "lazy".
The most threatening predator to sloths is the horned eagle. Rory Wilson, a biologist at Swansea University in the United Kingdom, once said: "They are powerful eagles, with the most terrifying claws and terrifying beaks. Faced with them, the sloth has little hope of surviving. nothing."
However, looking at the monkeys running around in the forest, the sloth turned his head and smiled slightly, thinking of a plan: as long as I am slow enough, the horned eagle will not be able to see me.
Indeed, as long as the sloth is slow enough and has the blessing of protective color, no matter how good the vision of the horned eagle is, it is not easy to find the sloth hidden in the woods.
Speaking of camouflage, sloths are masters, and are born equipped with "auspicious clothes" (click to learn about auspicious clothes). That's because the sloth's fur is a breeding ground for numerous microbes and algae.
A study of the sloth's hair has shown that almost every hair on the sloth is folded in half, a structure that forms a paradise for the growth of a variety of algae, which scientists can't rule out are also beneficial to the sloth's health.
Some algae grow on the sloth's body, especially in the longer hair on the head and neck, and "inhabit" some small insects that live in symbiosis with the sloth, such as sloth moths, which are decomposed by microorganisms after death Can be used as food for algae.
These algae and microorganisms are the best equipment for sloths to "hide" in the canopy, and wild sloths are basically green. So scientists speculate that the main reason sloths are so fond of the algae and microbes that live in their hair is for camouflage.
In addition, the sloth is an animal that "digests" extremely slowly.
The stomach of a sloth is twice the size of an animal of the same size and accounts for 1/3 of its body weight. The process of food digestion and absorption through the stomach and intestines is extremely long. A study shows that it takes up to 50 days for food to enter the sloth's mouth and finally excrete it. It really interprets the slowness very thoroughly.
This characteristic of finding ways to completely squeeze out food nutrients also reduces the risk of sloths being predated during foraging.
The editor imagined that the taste of sloths with "grass" would not be very good, but I don't know what their natural enemies, horned eagles and jaguars, think.
"Regenerator" Starfish
The well-known Pai Daxing in "SpongeBob SquarePants" is a bulky, silly-looking "optimist". And its prototype, the starfish that lives on the bottom of the sea, moves slowly, but is still very alert when facing predators.
How do slow starfish walk? We have to understand the structure of starfish first.
Starfish are mostly in the shape of a five-pointed star, with five arms protruding from the central disk, but there are also more arms, such as sun starfish, which generally have 10 to 15 arms.
On the ventral side of the wrist, there is a step belt groove, and 2 to 4 rows of podia protrude from the groove. The tube feet are formed by the end of the upper sac of the starfish's water pipe system. The water pipe system is filled with liquid. When the starfish moves, these structures are equivalent to a set of hydraulic devices. The movement of the starfish in the sea depends on the coordinated contraction of the pipes and other parts of the water pipe system. Achieved.
Although it has grown a lot of tube feet, it is not easy for starfish to run when facing danger. But it possesses another powerful survival skill - regeneration of severed limbs.
Starfish has a very strong regenerative ability, a wrist with a small part of the central body disk tissue can regenerate a complete individual, especially with the sieve plate (the small circular plate at the edge of the central disk, which is the connection between the water pipe system and the outside tissue. connection) is easier to regenerate.
There is also a finger starfish (Linckia), which can regenerate the central disk and other arms with only one wrist tissue, but the size of the regenerated parts will be smaller than normal.
In this way, when in danger, the starfish can cut off the wrist by itself, distract the attention of the predators, and then escape. Anyway, a new wrist can grow again. Starfish's powerful regeneration skills are reminiscent of Wolverine, one of the superheroes, and its strong healing ability makes Wolverine invincible.
Not only can starfish cleverly escape the predation of natural enemies, it is also a terrible predator itself, and it likes to prey on bivalve molluscs such as oysters and mussels. Starfish have two stomachs (cardia and pylorus). When encountering prey, they spit out the cardia stomach, slowly corrode the prey with digestive juice, and then retract the stomach.
In addition, the red eye spots at the end of the starfish's wrist are photoreceptors, which together with the chemoreceptors around it can quickly find prey in the water.
Although it moves slowly, but with so many special skills, it is not a problem for starfish to survive in the sea full of predators.
"Self-baptized" hedgehog
Everyone is familiar with the hedgehog. Its biggest feature is that its body is covered with short and dense spines. Some people may ask, even if the hedgehog moves slowly, it has a "sharp weapon" and won't make predators flee?
Indeed, the spines of a hedgehog are its best weapon. When it is threatened, it will curl up its body and form a ball of spines, wrapping its soft abdomen and limbs inside, and erect its spines like Rong Rong "Prick the needle". Generally, small animals with weak combat effectiveness see such a big thorn ball, not to mention that they have nowhere to bite, even if they want to get close.
However, the natural enemies of hedgehogs are mostly carnivores such as skunks, owls, and foxes. They are not vegetarians, and they have various methods to make the hedgehogs covered in thorns submit. For example, the skunk will look for the gap on the thorn ball and "fart" at it, and the hedgehog will stretch its body after being paralyzed.
In addition, unlike sloths, hedgehogs can stay in trees for camouflage all day to reduce the danger on land, and they need to forage everywhere. Hedgehogs are nocturnal and mainly feed on insects. However, when it is slowly looking for insects, it is likely to be crushed to death by a fast-moving vehicle. This is not uncommon. It can be seen that the slow movement of the hedgehog still poses a certain threat to its survival.
However, hedgehogs have a way of "self-baptism" that allows them to avoid predators. This is the "stinging behavior" of hedgehogs. After chewing some plants in the surrounding environment, they will smear each thorn on their face, abdomen and back with saliva mixed with juice, so that it is different from the surroundings. The environment keeps the same smell to play the role of "stealth" and prevent natural enemies from finding themselves.
Another function of thorn painting is to apply some poisonous substances on their thorns. If natural enemies attack, the poison on the thorns will also add a layer of protection to the hedgehog. For example, some hedgehogs will chew the skin of toads and kill the toads. The venom of the toad is applied to its spines, and the hedgehog itself is quite resistant to the toad's toxin and will not hurt itself.
In fact, it is hard to imagine how hedgehogs lick every thorn with their tongues. After all, it is very difficult for us humans to see our own backs without looking through a mirror. So the editor has been wondering about the ability of hedgehogs to paint spines until I saw this picture.
Some people who keep hedgehogs as pets have a confusing behavior, that is, if they are bitten by their little hedgehogs, instead of getting angry, they will be very happy. The reason is that they think that hedgehogs bite themselves to paint their thorns, that is, to accept the taste of their masters. Actually otherwise, the hedgehog bites you most likely because it was frightened by you! If you are bitten by a small animal, timely disinfection is the most important thing, don't be silly anymore.
Finally, I would like to praise this small mammal with thorns all over its body. They like to eat insects and can eat more than 200 insects in one night. They have removed many pests for agriculture and forestry, and are good friends of human beings.
Slow action does not allow some animals to have agile escape skills, but in order to survive, these "slow" animals have evolved ingenious countermeasures to avoid predators. So do you know any tricks for "slow" animals to avoid natural enemies?
The article comes from Baijiahao Beijing Science Center