Ruling dynasties of spotted hyenas: why does matriarchy reign in their clans?

Some animals have the most disgusting reputation among people. This certainly applies to hyenas. In almost all languages of the world, this word means a vile, stupid, unscrupulous creature, ready to pounce from the back at any moment. However, in the real world, things are much more interesting.

Hyenas are actually smart and successful. One of the species of this family forms numerous flocks with a very rigid social hierarchy. And females rule in them, which is extremely unusual for wildlife. These matriarchs eventually pass the position at the head of the group to their daughters. Thus, we are dealing with something like a dynastic rule.

Scientists have long tried to figure out how and why this pattern of behavior appeared. Is it acquired during life or transmitted at the level of instincts? It turns out that both answers are correct to some extent.

Female spotted hyenas (Crocuta crocuta) are wonderful creatures in every way. The most worthy of them lead packs, the size of which can exceed 120 individuals and they are called clans. Physically, they are larger than males and noticeably more aggressive than them. It is generally accepted that both of these traits are determined by androgens - hormones that play a crucial role in the development of male sexual characteristics. One of these is the well-known testosterone.

Androgens are produced by both males and females of all vertebrates, but the males usually produce them in much greater quantities. In spotted hyenas, meanwhile, the opposite is true for at least some of the hormones of this genus.

It is even more difficult with testosterone in their case. Usually females have less testosterone than males. However, this situation changes after pregnancy. Closer to childbirth, the level of androgens in the body of the female hyena begins to rise. And how they act at this point in time on the developing fetus determines, so to speak, the “personality” of the future hyena. Hormonal cocktail increases the level of her aggression for a long time.

In 2001, a research team published the results of their study, which found that the higher the social status of the mother, the greater the concentration of androgens in her body during pregnancy. This means that the cubs born to these matriarchs will be more aggressive than their relatives with low status, and will be able to take a higher position within the clan. Hyenas, by the way, are the first mammals in which the mechanism of "genetic transfer of power" was discovered.

Meanwhile, exposure to androgens increases aggressiveness not only in future females, but also in males. On the one hand, it is clear that this processing is designed to maintain the authority of the "ruling dynasty", on the other hand, it is not clear why matriarchy should reign here. In this regard, scientists have suggested that after the birth of the females, they undergo something like a training course on managing their wards. An interesting study report on this topic was published in 2018. Its authors have been observing the behavior and interactions of eight packs of spotted hyenas in Tanzania for a decade.

Particular attention was paid to those who emerged victorious in the clash of two hostile individuals. The results of fights were recorded both between representatives of the same flock and different ones. Attention was paid to where the fighters grew up - in their current group or joined it.

It turned out that hyenas with more support within the pack most often win. Gender was completely irrelevant. The best results were shown by females, since their social bonds were invariably stronger than those of males. Scientists have found that hyenas almost always support their direct relatives during these squabbles.

Thus, the high social status of females is ultimately reduced to the issue of consanguinity. The fact is that most males leave their clan and go to another one when they reach puberty. Why do they do it?

Most likely, we are dealing with an evolutionary stopper that prevents inbreeding and promotes an increase in genetic diversity. As a rule, such breeding tactics lead to the birth of healthier offspring. Females remain within their family, and this is what forms communities in which matriarchy reigns.