In the animal world, males are labeled "losers" when they fail to join another group to breed. Contrary to common belief, researchers from the Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin, Germany, have found that stay-at-home male spotted hyenas can breed just as successfully as their more adventurous competitors that leave home.
Spotted hyenas live in matriarchal social groups, where females have complete control over mating decisions. In other words, a female chooses which male they wish to be the father of their offspring. Young females, for example, prefer males that were born or that joined their clan after they were born, thus allowing them to avoid incestuous breeding with their father or older brothers.
Generally, males that disperse from home to breed elsewhere are thought to father more offspring. In a first-of-its-kind study, researchers have confirmed that homebody (philopatric) males and dispersers are not inherently different and have similar reproductive success.
But how do hyenas choose to stay or leave home? The research team found that this choice is largely driven by which group - the birth clan or a foreign clan - offers the best fitness prospects- in other words, which group contains the youngest females when a male is ready to start breeding, thereby increasing his chances of fathering a cub.
For the past 20 years, researchers examined an entire population, including eight distinct clans, of spotted hyenas living in Tanzania's Ngorongoro Crater. By observing the behavior, survival and reproductive success of more than 250 males, researchers were able to examine the causes and fitness consequences of male clan choice.
Clan size and number of young females naturally fluctuate due to chance and environmental effects. While researchers found that most hyena males in the Ngorongoro Crater dispersed to another clan, more males inevitably stayed at home than expected. This suggests that being a homebody has its advantages.
"Mothers provide social support to their stay-home sons and ensure they acquire a high social rank among breeding males. This gives the mama's boys privileged access to both food and females, allowing them to invest a lot of time consorting females," explained Eve Davidian, a doctorate candidate from the IZW.
Genetic paternity analyses revealed that males breed almost exclusively with high-ranking females and father their first cubs at a younger age when staying at home.
Their study was published in the March 18 issue of the journal Science Advances.
