Post #14762

Caring frogs: Bear babies in their stomachs and give birth through their mouths The stomach is needed to digest. There is an extremely aggressive environment: burning acid, various enzymes and constant contractions - if something gets inside, there is no chance. But the caring frogs swallowed their eggs, and after 1.5 months ready-made little frogs jumped out of their mouths. You have never seen a more strange way of bearing offspring! But how is this even possible? Why weren't the baby tadpoles digested in their mother's stomach? It’s all about an extremely unusual strategy: the stomach of caring frogs turned into a “gestational sac”, a kind of uterus, during the period of bearing offspring. Today, none of the animals uses such a device - females either lay eggs and eggs in the external environment, or bear their young where nature intended. Therefore, it is doubly interesting to figure out how frogs even adapted an organ that was absolutely unsuitable for pregnancy to raise offspring. Most species of amphibians are ready to become parents in the first year of life, but caring ones preferred to first stand on their paws, grow and gain life experience. And only then 2-3 year old females paid attention to the serenades - the louder the cry, the more enviable the groom! Males sang in their area of ​​the reservoir, in rock crevices and among stones, trying to attract as many females as possible. Due to the very difficult “pregnancy”, the frogs could only bear one litter of tadpoles per year, and the cavaliers did not have many chances - not a single one could be missed. After the fateful meeting, mating and external fertilization took place - exactly at this moment ordinary things end. Then the crazy biology begins! On average, female frogs lay from a couple of hundred to several thousand eggs, but most of them will die in the first months of life. The strategy is very simple - the more children, the greater the chance that at least one will continue the family line. About 80% of amphibians do this. But our caring ones limited themselves to only about 40 eggs. They had a completely different tactic of maximum parental care, almost unusual for amphibians. After fertilization, the female swallowed the eggs, provoking a radical restructuring of her insides. Frog eggs were also unusual, with a large supply of nutrients and a thick jelly-like protective shell. At the same time, the embryos inside the eggs produced the hormone prostaglandin, which triggered a cascade of changes in the mother’s body. In fact, prostaglandins have a wide range of effects: depending on the site of action, they can dilate or constrict blood vessels, regulating blood flow, and can trigger inflammation and increase pain. And these hormones also work in two completely unrelated directions: they affect the development of the fetus and the regulation of certain processes in the gastrointestinal tract. More specifically, prostaglandins reduce acid production in the