The delivery of male seahorses represents a step forward for evolution

The phenomenon of expectant fathers also observed in another species. The delivery of male seahorses is a step forward for evolution.

In the Treccani dictionary, the word "pregnant" is classified as a feminine adjective. No word on a masculine form of the same term, which in fact sounds decidedly odd: can you say "pregnant"? The grammatical dilemmas, which on paper might seem like a somewhat abstract matter, become decidedly more prosaic when we start talking about seahorses.

How do male seahorses give birth

It works like this: after finding a mate, the female seahorse deposits her eggs in a sac in the body of the male specimen. Once the eggs have been placed in the sac, the male will proceed to fertilize them, and then hold them in his lap for about 24 days, during which time the embryos grow and develop.

Those who have witnessed the birth of a male seahorse have sworn that it is an exceptional spectacle: the father does not experience any fatigue or effort, while the young, which can be thousands in a single pregnancy, begin their lives by taking the road to the sea like so many soap bubbles originating from a ring. But how is it possible that nature provides for such an exception, when in almost all other species of animals it is always the female that gives birth?

The exception of seahorses depends on an evolutionary leap

It should first be noted that what we observe in seahorses also occurs in needlefish. A research, recently published in the scientific journal PNAS, has in fact observed both species to discover the genes that allow the males of seahorse and pipefish to arrive at childbirth, preventing the immune system from attacking the embryos, which in fact would be a "foreign" element from which the organism may also want to protect itself.

The interesting part of the study classifies such a phenomenon as an evolutionary trade-off, which is all in all to lose some features to gain others. In the case of expectant fathers, the immune function, i.e. protection of the organism from external agents, classifies embryos that are not their own as an exception, allowing, for the first time in nature, male specimens to remain... "pregnant"? Can we say that?

This is not the only exceptional aspect of the animal kingdom. For example, scientists have observed the way bees figure out what time it is. In Germany, then, there is the ant that never ages and hides a terrible secret.

Giuseppe Giordano