Unlike humans, animals do not seek meaning in life. For them, it is extremely clear: to multiply and reproduce, so that the biological species does not cease to exist. At the same time, some representatives of the fauna use the k-strategy: they rarely breed, but accurately, surrounding their offspring with love and care. Others - r-strategists - on the contrary, take in quantity and do not waste time raising their offspring. In both cases, the goal is achieved. And sometimes it is very intricate …
LIVING MONUMENT
A living monument of South American nature. This is sometimes called a miniature frog that lives in the mountains of Chile. It was there, in a cool stream, that Charles Darwin discovered her during his famous round the world trip in 1834. At first, however, it seemed to him that under his foot was a withered leaf of a tree. However, when he suddenly came to life, Darwin realized that he had nearly crushed one of the wonders of nature - tiny, sharp-nosed, unique! Nowhere, except in South America, this frog is no longer found. However, the true glory of Darwin's rinoderma, named after its discoverer, was not brought by its miniature size - but the adult individual barely reaches 3 cm in length, not the ability to change skin color from dark brown to light yellow, and not even its rarity, but the way it is carried and the birth of children.
To begin with, the role of the mother in this pair is assumed by … the father. It is he who takes the blow of pregnancy and selflessly bears children. The task of the female in this tandem is to lay eggs. The father's task is to impregnate and … swallow them. After all, the throat sac serves as the "womb" of Darwin's rhinoderm.
The mother frog lays one or two eggs at a time. The male diligently "eats" them. But, you know, none of them get off at once. The mating season for Darwin's rinoderms lasts from December to February: and for two or three months the frog lays eggs, and the male swallows them. So the throat sac fills up gradually, stretching out and overflowing with future frogs. And if at first it is small, narrow and short, but by the end of February it may well sink to the very rear end of the rhinoderm body. As a result, a heroic father bears up to 25 cubs in one pregnancy. And this is another feat!
The embryos behave well at first: they feed on the yolk contained in the egg. But when his reserves run out, they begin to parasitize at the expense of the pope. To this end, the babies attach to the walls of the father's throat sac, rich in capillaries, grow together with it and live happily ever after until they acquire their own tail and fins. Then they leave their ancestral home - and the male, who regurgitated his offspring, finally gets the opportunity to breathe calmly. Until next December.
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WHEN CHILDREN'S NICK
Nosed rheobatrachus - the name of our next heroine, a resident of Queensland, sounds so poetic. This frog has chosen the northeastern state of Australia since time immemorial: it may be one of the first Australian aborigines. And, being a true daughter of his continent, he is ready to throw out different knees. Although, at first glance, this cannot be said - the frog is like a frog: rather small (up to 5 cm), gray, not too active, if not lazy. Judge for yourself: nosed rheobatrachuses are excellent swimmers, but they prefer to sit motionless for hours on land, and move in the water, drifting on their stomachs. It seems like their motto is: don't worry, be happy.
However, this sloth at one time presented a surprise to zoologists when they found out how the nosed rheobatrachuses reproduce. It turned out that the females swallow the fertilized eggs. It would seem that nothing new: after Darwin's rinoderma, it is not so easy to surprise us! But the nasal rheobatrachus succeeds: after all, the brood chamber, the "uterus", serves the female … the stomach. He acts in this role for 7-8 weeks, as long as the pregnancy lasts. And all this time the female does not eat anything! Her body begins to actively secrete prostaglandin E2. This active substance turns off the production of gastric juice and thereby protects future frogs from digestion. So nothing threatens them in my mother's stomach. That is why, apparently, having hatched from the eggs, the baby tadpoles are in no hurry to leave the mother's womb. They prefer to stay inside the frog to the last. The internal organs of the nasal rheobatrachus grow and squeeze. Because of which, the female has to slow down her metabolism and increase gas exchange through the skin: the squeezed lungs cannot cope with the load. In a word, do the kids scoff at mom? as they can. And she endures everything, which is why she received the nickname "caring frog": after all, this is the only frog in the world that does not give birth to tadpoles, but completely ready, formed frogs.
At one point, they simply cease to fit inside the stomach, and then labor begins in the nasal rheobatrachus. The process of childbirth can take a whole week: the mother regurgitates offspring in small batches. At the same time, some individuals are categorically not ready to face the harsh outside world and try to get back into the stomach of their mother. But this number does not work for them, because the frog is constantly sick of new and new children. This protracted process gives her little pleasure. Therefore, if you ever come across a giving birth rheobatrachus, keep in mind: the frog needs to be scared properly and thereby relieve it of its torment - from fear it will at once vomit all its children out of itself.
ROLE-PLAYING GAMES
They say that in order to make sure that the Creator has a sense of humor, it is enough to look at the platypus. And to be convinced of God's remarkable fantasy, it is enough to look at the common bitter - a small freshwater fish from the carp family. This surname is very numerous; at the last count, it includes 2300 species. But almost each of its representatives - praise the Creator - has its own flavor. So, nature has provided the common bitter with an ovipositor, which is inherent exclusively in arthropod representatives of the fauna. A special organ for laying eggs in the bitter beetle is a process on the belly that allows it to spawn in hard-to-reach - and therefore safe - places. But what is a safe place? Gorchak is sure that these are the shells of bivalve mollusks - pearl barley or toothless.
When the mating season comes, the male bitter cap finds suitable mollusks and drives away from them “competing firms” - other males. The female swims up to the "incubators" and, with the help of the ovipositor, lays eggs in the open shell of the mollusk. The latter does not like such impudent interference in his personal space at all, and therefore he slams the shell and … finds a "foreign body" inside himself. In an attempt to get rid of it, the mollusk begins to pump a large amount of water through itself. In vain: the surface of the bitterness eggs is covered with horny teeth, which firmly adhere to the living incubator. And as if there is not enough humiliation for pearl barley and toothless, so also the male releases milk and fertilizes the eggs. This is where the comedy finita happens - the mollusk turns into a surrogate mother. However, he does not suspect it and until the very last does not stop trying to get rid of the "foreign object" by opening and closing the shell and thus ensuring the fry an uninterrupted supply of fresh water. Therefore, they are in no hurry to leave their "house" and decide to go out into "open space" only when they are properly strengthened.
But wait, sympathize with the clam! He is also a guy not a mistake: his surrogacy is well paid. While the gorchak lays eggs and throws milk, the mollusk brings down its own larvae - glochidia - on it. They penetrate under the skin of bittersweets and are there until the very end of larval development. And after emerging from "infancy", they fall away from the fish and embark on an independent voyage. In fact, they use bittersweets both as surrogate mothers and as a means of transportation. So it remains to be seen who owes whom more …
Natalia KUVSHINOVA