The new hypothesis explains why male and female lemurs are about the same size

In a work published recently, biologist Amy Dunham of Rice University has come up with a new hypothesis that explains one of the longest secrets of primates: why male lemurs and the same is the same size.

In most primates, females have evolved to a size larger than males. Body size is an advantage that helps males protect their offspring from the 'attack' and dominance of other males. However, evolutionary biologists have long wondered why lemurs do not follow this rule.

'This is a big question that scientists debate over the past 20 years,' said Dumham, a professor of ecological and evolutionary biology research. 'I really started to study this species ever since I came to work in Ranomafana (National Forest in Madagascar), and the question of the size mystery of lemurs has pursued me over the years.'

In an article published on the cover of the Journal of Evolutionary Biology this month, Dunham presented one of the latest hypotheses that explains the general size of two varieties of lemur.

After scrutinizing all the observations carried out on lemurs, Dunham came to the conclusion that in this species, like other primates, males protect their mates. But unlike gorillas and the rest of the species that often fought to gain the right to mate with females, male lemurs protected their mates passively.

They do this by secreting a knot of fluid inside the female reproductive tube at the end of mating.This button was originally in the form of liquid protein, but then it quickly became solid and stayed inside the female for 1 to 2 days . Many females only respond to males' desire once a year, so the button acts to prevent other males from mating with the females while still allowing the male to mate with the females. others.

"If children only meet mating for a short period of time like lemurs, we think it is a beneficial strategy," said Dunham, co-author of the study with biologist Volker Rudolf. .

To test their hypothesis, Dumham and Rudolf examined 61 species of primates and found that the intersection usually occurs in species where the mating response time is very short and two varieties have the size equal ruler.This phenomenon is not only present in lemurs, but also in some other species, such as South American squirrel monkeys.

'Our opinion needs more testing time, because this is a new hypothesis in more detail than the previous hypothesis. Now we are anxious to conduct further research, ' Dunham said. 'We have had some specific predictions about the conditions that arise for this phenomenon, so there are many ways to implement testing.'

Dumham said she hopes to reach Madagascar in the next year to begin collecting data from a new project that examines the effects of climate change on lemur populations.

Lemurs evolved on an African island and isolated the primates world for 65 million years, and they are famous for having many differences compared to the rest of the primates. For example, some lemur individuals hibernate, store fat in their tails, and all lemurs have their teeth designed like a comb for combing.Lemurs also differ fundamentally in a mystery to the scientific world: like this species is the dominant species.

Dunham's investigations of the secret relate to the dominance of lemur females making her make another important hypothesis last year. The content of this hypothesis is detailed in Animal Behavior, in which female lemurs tend to overwhelm male lemurs because the females take on the role of taking care of their children, so it has more will to fight and win.

'Game theory predicts that when two opponents' fighting ability is equal, the outcome of the battle will depend on the value of the fighting engine of each party,' she said. 'In this case, the children obviously face more dangers, but the only reason females gain advantage over males is because both have the same size and strength.'