As the crocodile says. Some sound like a bell

02/16/2017 Texts / Articles

​It turned out that they love to play ball

Recorded: Maria Melnikova

Photo: photo courtesy of the Enlightener Prize

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Crocodilians are crocodiles, alligators, caimans and very photogenic animals called gharials. The image of crocodiles, familiar to us from school curriculum and from books - lazy log-like creatures that do nothing and only eat someone from time to time. When I started writing my dissertation on them, I, in general, guessed that in reality things were not quite like that. The question that interested me first of all was this: it is known that 65 million years ago there was a mass extinction - all dinosaurs, except birds, died out, almost all large fauna and a huge number of small ones died out... and the only large animals that survived this catastrophe , were crocodiles. They haven't changed much since then. What is so unique about them that allowed them to survive all this and exist happily ever since? The first thing I started doing was communicating with them.

How do crocodiles communicate?

It is known that crocodiles and alligators became independent branches of the evolutionary tree even before the extinction of the dinosaurs, that is, approximately 70 million years ago. Then their languages ​​diverged, but even today they more or less understand each other. If a crocodile threatens an alligator, then the alligator knows what they want to tell him. By comparison, human languages, when they diverge, become mutually incomprehensible after about 500 years. What is so good about the crocodilian communication system that it is so conservative and changes so little over time?

It would be impossible to study the entire crocodylian language at once, since a dissertation must be completed in 5-6 years, and not in three lifetimes, so I decided to concentrate on the signals they use during the mating season. Since the signals of males and females are different, I decided to make my life even easier and focused only on the signals of males. During the mating season, male crocodiles sing. To our ears, this, of course, does not really sound like songs. The male alligator raises his head and tail, begins to sway, and in one phase he roars, and in another he emits infrasound. At this moment the water boils on his back.

The alligator's roar sounds like a tank engine starting up. It spreads very far through the air above the surface of the water, but almost never gets into the water. Only males produce infrasound, and this feature is the most convenient way to distinguish males from females. Its frequency is approximately 10 Hz - this is slightly lower than what we hear. If you are very close to a crocodile, you will catch it, but in general this is not necessary, because you feel it with your whole body, these are very strong vibrations. If you look at a singing alligator from above, you can see that infrasound is generated not in the vocal cords, but by vibration of the chest wall. In this case, a pattern of dancing water drops appears - the so-called Faraday waves. When I was doing this, it was believed that it was by-effect, which has no meaning, but it has since become clear that it is a visual signal for other animals.

Why do crocodiles slap their heads?

In addition to roaring and infrasound, crocodiles also slap their heads. Species with very narrow heads snap their jaws above the surface of the water. Why do we need three? different types sounds that at first glance have the same function? I thought that these three types of sounds spread differently and convey information in different ways: “I’m swimming here, all this big handsome male - girls, swoop in!”
Infrasound travels very far across the water, almost unlimitedly - with its help, whales hear each other hundreds of kilometers away. But from infrasound it is very difficult to understand where it is coming from, and besides, the frequency is almost the same for all animals. You only know that somewhere there is a big healthy male - in order to produce infrasound underwater, you need to be huge - but you don’t know where he is. And if there are several males, you cannot understand which of them the sound comes from. It is very easy to determine from the slaps where they come from. They carry better over water, but they can also be heard well in the air. The roar travels only through the air. If you are in different ponds with an alligator, then the infrasound most likely will not reach you, but the roar and slap will. If you are in the same river, then infrasound will reach you much better than a roar. Therefore, it is logical to assume that if a crocodile lives in a large river or lake, then it is more profitable for him to use infrasound and slaps, and if he lives in a small swamp and wants to be heard in neighboring ones, it is better for him to use roars and slaps as direction indicators.

Some sound like a bell

I have a theory: the differences between the sound signals of different species are due to where those species live. Since crocodiles live on different continents, testing the theory took many years and took a huge amount of effort and money. But it turned out that there are actually 15 species that do not live in any specific type of habitat, but “anywhere,” and use all types of signals equally. 7 species that live only in small bodies of water roar, but do not use splashes or hardly use them. And 5 species that live only in large bodies of water, on the contrary, splash, but almost do not roar, and if they roar, the roar is very weak, reduced. The only exception is the gharial; in addition to roaring and clicking its jaws, it has another special sound - no one knows how it makes it. This sound is a bit like a cracked bell, it travels underwater, and the gharial apparently uses it instead of infrasound.

About the hierarchy of crocodiles, songs and dances

During the research it became clear interesting thing: In alligators, populations varied little in their use of roars, but varied greatly in their use of slaps. But for crocodiles it was the other way around - populations varied greatly in the use of roars, but the number of slaps was almost the same. It took me a very long time to understand why this was happening. And the following idea arose: in both crocodiles and alligators, one of the signals can have a second function. And it turned out that among crocodiles in each group only the dominant male, the “master of the harem,” sings. If another male tries to roar, he will have a very hard time. With alligators it’s the other way around - they do not have a strict hierarchy, but have a complex social structure that is still incomprehensible to us. But their roar has an additional function. Unlike crocodiles, alligators sing in chorus, and I was surprised to discover that they also dance. The dancing takes place at night and is a very interesting spectacle. It's easy to see, but no one has done it before. All alligators who participate in these group dances and choral singing benefit from having as many participants as possible present and a larger selection of potential partners. Alligators need to roar in order to attract as many animals as possible to the dance routines.

Where and why do alligators and crocodiles dance?

The dynamics there are similar to village dances: you can come with a girl or alone, it’s not a fact that you will leave there with the girl you came with, and you can also come there simply because you want to fight. There is such a crush there that it is very difficult for an outside observer to understand who is with whom and what is happening, but the alligators somehow navigate it.

Now several people are trying to decipher social structure alligators. It turns out that they are quite promiscuous, but most adults have favorite partners with whom they meet year after year. Often they come to the dance with their favorite male or female and leave together, but sometimes everything changes. Occasionally there are fights there, and quite serious ones - sometimes animals die. Courtship also takes place there - many alligators swim alone and swim away in pairs. Nothing like this happens in crocodiles - at least no one has ever seen anything like it.

The crocodile signal system can be adapted to any habitat. This flexible system so good that there is no reason to change it. I think that's why it has existed for millions of years.

How do crocodiles hunt?

Crocodiles' hunting methods are much more varied than they say in books. They are believed to be primarily ambush hunters, waiting for prey at the water's edge. However, when researchers attached small cameras to the alligators, they learned that they actively swim all night and hunt underwater for fish, crayfish, snails, and small turtles. And I discovered that they can hunt on forest paths very far from water - at a distance of 50 meters.

What interested me the most is when they hunt in a group. The most amazing hunt I saw was in western New Guinea. There was a large lagoon with a path of trampled mud running through the middle of it. At low tide it rose above the water and was used by pigs, dogs and others. local residents. Crocodiles used different tactics depending on what kind of animal was walking along the path. They understood that they could simply grab a calf by the leg, but this trick would not work with a pig.

One day I was sitting in a tree and watching, and a pig was walking along the path. On one side of the path there was a big, big crocodile, and on the other there were two smaller crocodiles. As soon as the pig caught up with big crocodile, he attacked her, but not in the way they usually attack, but behaved the way crocodiles behave when trying to scare someone away: he opened his mouth and ran at the pig with a terrible roar. The pig got scared, for which it’s hard to blame her, and rushed into the opposite side, ended up on the second half of the lagoon, two small crocodiles immediately grabbed her and tore her apart. Big crocodile He happily ran across the path, and then there was only contented slurping. And I got the impression that the three crocodiles had planned all this in advance, because the path was elevated and they could not see each other. But I only had the opportunity to observe this once.

Alligators in Louisiana hunt like this: they are divided into two groups, large animals separately, small ones separately. The big ones drive the fish from the deep part of the pond to the shallows, where small alligators wait for them. Both groups then meet and share the fish among themselves. Several people have already seen this.

Swamp crocodiles in Sri Lanka swim in a circle around a school of fish, and this circle becomes smaller and smaller and smaller, and then the crocodiles begin to take turns swimming through the center of the circle and grabbing as many as they can.

In one reserve in Asia, where there were a lot of herons, I noticed that crocodiles often swim with twigs on their heads. I thought it was just such a great disguise, so I took a photo of it and moved on. Then I came across the same sight in Florida, where there was also a large colony of herons. Then it dawned on me that this might not be a coincidence. During the nesting season, herons are sorely lacking building material, they are constantly looking for twigs, stealing them from each other’s nests, because of this, fights occur... And a crocodile with a twig on its nose has a very good chance of attracting a heron, which will try to grab this twig. I did a little research in Louisiana, and it turns out that alligators actually swim with twigs around heron colonies and specifically during nesting season. All this shows: in terms of the variety of hunting methods, crocodiles are second only to humans. Just 5-10 years ago no one knew anything about this.

Crocodile kindergartens and ball games

Crocodiles also have a lot of different interesting elements of behavior. For example, a kind of care for offspring. Alligators have nurseries, which females guard in turns. It also turns out that crocodiles love to play. People who worked with them professionally in nurseries knew about this, but it did not leak into the scientific literature at all. It turned out that different types crocodiles love to play with pink flowers. Many people love to play ball. There are several videos of crocodiles surfing in the surf. They play with ringing objects and streams of water. More cubs ride on your back younger brothers and sisters. The most interesting thing is that crocodiles can play with other species. I observed an alligator who regularly played with an otter. And the most interesting story happened in Costa Rica - there, 20 years ago, a local fisherman found a crocodile in the forest with a shot in the head, brought it home, went out and they became close friends. They swam together, played, pranked each other - the crocodile sneaked up from behind and tried to scare the man. Crocodile experts made gloomy predictions - they say, sooner or later a tragedy will happen. Eventually, the crocodile died of old age. During this time the man did not receive a single scratch.

In terms of complexity of behavior, crocodiles are not inferior to birds and mammals, and this has only now become known. How is it that such large and well-known animals were so poorly studied? There are several reasons. Firstly, when we talk about smart animals, we mean their ability to think like us. Anyone who thinks differently is usually not perceived by us as very smart. Secondly, time flows differently among crocodiles. He can lie on a hummock for a month, without moving once during this time, and wait for something interesting to happen - for example, spring will come. Most people simply don't have the patience to watch crocodiles. It was very difficult for me. The third reason is that all the most interesting things among crocodiles happen at night, and for some reason it never occurred to anyone that it was necessary to study crocodiles in the wild and at night. Once I started doing this, I came across alligator dancing within the first week. The fourth reason is that cold-blooded animals seem less attractive to us than warm-blooded and fluffy ones. And one more difficulty - most of what I just talked about is impossible to observe in captivity.

Answer from Nina Tikhevskaya[guru]
Of course, the crocodile cries not out of pity for its victim, but because of its physiological characteristics.
Anatomically, the skull of a crocodile is designed in such a way that when it eats a prey, it cannot immediately swallow it, although it tries. The crocodile captures large pieces of food: during a hunt (a sudden sudden attack), it simply cannot bite off a “piece of ham.” here lies the reason for his tears: from a physiological point of view, a CROCODILE CANNOT CHEW. his jaw is not designed for this. and he is forced to swallow big piece food.. This puts pressure on the lacrimal sacs, and the crocodile cries.
Figuratively: I think everyone here knows the expressions “choked,” “choked,” or, as they sometimes say, “a piece got stuck in the throat.” a person who is choking (coughing from something that interferes with breathing - in this case from food) has tears in his eyes.
The situation with “crocodile tears” is similar.
In addition, the crocodile has imperfect kidneys. To remove harmful toxins and excess salts from the body, the crocodile has developed special glands that open outward near the eyes. When they work, it seems that the predator is crying.
In short, jaw movements distort the lacrimal glands and release tears. A crocodile, like a human, for example, has salty tears, i.e., they participate in maintaining the salt balance of the body. Simply put, a crocodile pees with its eyes. :))) Do you know the saying? “Cry more, pee less” This is about small children, but it’s also suitable for crocodiles. :)))

Answer from T B[guru]
Well, not out of pity for the victim. This is their nature - after eating, salt streams are released from the eyes.

Answer from Tatyana Zakharova[newbie]
excess water seems to be in the body

Answer from Tree of Destiny[guru]
from onions))

Answer from Ms Fanta[guru]
And I definitely will! This is how they remove excess salts from the body!

Answer from Anatoli Rosljakov[guru]
I feel sorry for the bird

Answer from AlexFill[newbie]
hmm... do they actually cry anymore?!

Answer from Nikita Yashkov[guru]
Indeed, Tiger Cub is right. Crocodiles cry while eating.
Scientists have been able to prove for the first time that crocodiles actually cry while eating.
According to Washington ProFile, the discovery was made at a crocodile farm, where scientists observed four caimans and three alligators (all of which are close relatives of crocodiles).
The reptiles ate food on land, this is a common method of feeding predators, which is why zoologists came to the farm. In natural conditions muddy water It is difficult to follow the eyes of crocodiles. As a result, observations showed that tears flowed from the eyes of five of the seven reptiles while eating.
The study was conducted at the request of neurologists at the University of California, Los Angeles, who are studying the rare "crocodile tears" syndrome. The fact is that while eating, for some unknown reason, some people cry. When preparing the article, the researchers became interested in the reasons for the appearance of the expression and asked their colleagues to determine whether this phenomenon actually exists and how it is explained.
Neurologists from California contacted zoologists from Florida. They became interested in the problem and soon discovered that in the scientific literature there were many references to this phenomenon, but mostly of an anecdotal nature.
The first mention of crocodile tears occurs in the book The Voyage of Sir John Mundelein, first published in England between 1357 and 1371. This book, apparently written by a Frenchman from Normandy, describes travels in Asia, the Middle East and Africa.
Most of the facts contained in it are based on the works of real travelers and historians, and it also contains many stories about the Amazons, people with dog heads and other wonders. Among other things, there is the following episode: in Ethiopia “there are many crocodiles that cry when they eat a person.”
Zoologists were deprived of the opportunity to feed human meat to the experimental crocodiles, so they replaced it with regular beef, Washington ProFile notes. The reasons for the appearance of crocodile tears have not yet been established.

Answer from ????a????[guru]
There are many legends about the crocodile. For example, the ancient Greek scientist Aelian wrote that a crocodile, taking water into its mouth, pours it on the paths near the river and, as soon as a person or animal slips and falls, it attacks and devours them. In fact, crocodiles are not as bloodthirsty and treacherous as they appear in various stories. Only one species regularly attacks people - saltwater crocodile. Although, of course, one dies from the teeth of these reptiles more people than from any other animals.
One of the many either true or mythical stories about crocodiles tells that a crocodile, having devoured a man’s torso, for some reason wets his head with tears and only after that completes his feast. It's funny, isn't it? However, there are too many witnesses confirming this to simply not believe and laugh.
For a long time the key to this riddle was not found. Only relatively recently did the Swedish scientists Fange and Schmidt-Nilsson manage to uncover this secret. They proved that crocodiles really cry and explained why this happens: of course, not out of pity for their prey, but from an excess of harmful waste. To remove them from the body, the crocodile has developed special glands that open outward near the eyes. The glands began to work - and the crocodile began to cry with burning tears.

Answer from Violet Miracle[newbie]
to lubricate the eyes when on land

Answer from Natasha[guru]
Do crocodiles cry? Many have heard the expression “shed crocodile tears.” This is what they say about a person who pours streams of fake tears from his eyes for every reason. So, do crocodiles really cry or is it a legend? There are many legends about the crocodile. For example, the ancient Greek scientist Aelian wrote that a crocodile, taking water into its mouth, pours it on the paths near the river and, as soon as a person or animal slips and falls, it attacks and devours them. In fact, crocodiles are not as bloodthirsty and treacherous as they appear in various stories. Only one species of it regularly attacks people - the saltwater crocodile. Although, of course, more people die from the teeth of these reptiles than from any other animals. One of the many either true or mythical stories about crocodiles tells that a crocodile, having devoured a man’s torso, for some reason wets his head with tears and only after that completes his feast. It's funny, isn't it? However, there are too many witnesses confirming this to simply not believe and laugh. For a long time, the key to this riddle was not found. Only relatively recently did the Swedish scientists Fange and Schmidt-Nilsson manage to uncover this secret. They proved that crocodiles really cry and explained why this happens: of course, not out of pity for their prey, but from an excess of harmful waste. To remove them from the body, the crocodile has developed special glands that open outward near the eyes. The glands began to work - and the crocodile began to cry with burning tears.

CROCODILE

(An old, old fairy tale)

Part one

Once upon a time there was
Crocodile.
He walked the streets
He smoked cigarettes.
He spoke Turkish -
Crocodile, Crocodile Crocodilovich!

And behind him are the people
And he sings and shouts:
- What a freak, such a freak!
What a nose, what a mouth!
And where does such a monster come from?

The schoolchildren are behind him,
The chimney sweeps are behind him,
And they push him.
They offend him;
And some kid
Showed him the shish
And some kind of watchdog
Bit him on the nose.-
Bad watchdog, ill-mannered.

The Crocodile looked back
And he swallowed the watchdog.
Swallowed it along with the collar.

The people got angry
And he calls and shouts:
- Hey, hold him
Yes, tie him up
Take him to the police quickly!

He runs into the tram
Everyone shouts: - Ay-ay-ay! -
And run
Somersault,
Home,
At the corners:
- Help! Save! Have mercy!

The policeman ran up:
- What's that noise? What kind of howl?
How dare you walk here,
Speak Turkish?
Crocodiles are not allowed to walk here.

Crocodile grinned
And he swallowed the poor guy,
Swallowed it with boots and a saber.

Everyone is shaking with fear.
Everyone is screaming in fear.
Only one
Citizen
Didn't squeal
Didn't tremble -
This is the valiant Vanya Vasilchikov.

He's a fighter
Well done,
He's a hero
Daring:
He walks the streets without a nanny.

He said: - You are a villain.
You eat people
So for this my sword -
Your head off your shoulders! -
And he waved his toy saber.

And the Crocodile said:
- You defeated me!
Don't destroy me, Vanya Vasilchikov!
Have pity on my crocodiles!
Crocodiles are splashing in the Nile,
They are waiting for me with tears,
Let me go to the kids, Vanechka,
I'll give you gingerbread for that.

Vanya Vasilchikov answered him:
- Although I feel sorry for your crocodiles,
But you, bloodthirsty reptile,
I'll chop it up like beef.
I, glutton, have nothing to feel sorry for you:
You ate a lot of human meat.

And the crocodile said:
- Everything I swallowed
I'll gladly give it back to you!

And here he is alive
Policeman
Appeared instantly in front of the crowd:
Womb of the Crocodile
It didn't hurt him.

And Buddy
In one jump
From the mouth of the Crocodile
Jump!
Well, dance for joy,
Lick Vanina's cheeks.

The trumpets sounded
The guns are lit!
Petrograd is very happy -
Everyone rejoices and dances
They kiss dear Vanya,
And from every yard
A loud "hurray" is heard.
The entire capital was decorated with flags.

Savior of Petrograd
From a furious reptile,
Long live Vanya Vasilchikov!

And give him as a reward
A hundred pounds of grapes
A hundred pounds of marmalade
A hundred pounds of chocolate
And a thousand servings of ice cream!

And the furious bastard
Out of Petrograd:
Let him go to his crocodiles!

He jumped into the airplane
Flew like a hurricane
And never looked back
And rushed away like an arrow
To the dear side,
On which it is written: "Africa".

Jumped into the Nile
Crocodile,
Straight into the mud
Pleased
Where did his wife, the Crocodile, live?
His children's wet nurse.

Part two

The sad wife tells him:
- I suffered with the kids alone:
Then Kokoshenka stinks Lelyoshenka,
Then Lelyoshenka is bothering Kokoshenka.
And Totoshenka was naughty today:
I drank a whole bottle of ink.
I brought him to his knees
And she left him without sweets.
Kokoshenka had a high fever all night:
He swallowed the samovar by mistake, -
Yes, thank you, our pharmacist Behemoth
I put a frog on his stomach.-
The unfortunate Crocodile was sad
And he dropped a tear on his belly:
- How will we live without a samovar?
How can we drink tea without a samovar?

But then they opened