Tag Archives: males

Alpha Males: An Exception to the Norm, According to Groundbreaking New Research

Posted on by
Reply

Forget everything you thought you knew about alpha males: Major new research suggests that clear male dominance in primate societies is not a universal truth, indicating that in many species, females either hold equal power or may even surpass males.

Over five years, researchers gathered data from 253 primate populations across 121 species to investigate gender power dynamics. Rather than relying on generalizations, they meticulously documented behavioral patterns.

“We aimed to observe individual-level interactions, identifying specific conflicts rather than relying on overarching categories like ‘men dominate here’,” stated study co-author Dr. Dieter Lukas in an interview with BBC Science Focus. “We then assessed how frequently men and women actually come out on top.”

The findings challenge deeply-held stereotypes.

Out of the populations studied, male dominance was noted in only 25 of the 151 observed groups, where they triumphed in over 90% of contests against females. Female dominance was observed in 16 groups, while the remaining 70% displayed moderate or variable gender dynamics.

“Strict male dominance was a surprisingly rare occurrence,” said Dr. Ellis Fuchard, the author of a related study, to BBC Science Focus. “We were aware of existing literature and did not anticipate it to be the majority, but discovering it was under 20% was more surprising than expected.”

The frequency of sexual conflict—clashes between males and females—was also found to be considerably higher than previously thought, comprising nearly half of all adult disputes.

Lucas pointed out that most studies tend to focus exclusively on either males or females, with few examining the interactions between the two. “However, here,” he remarked, “the conflict between genders is clearly highlighted, showcasing frequent confrontations.”

A group of chakma baboons during a grooming session. To the left, a large male is groomed by a smaller female along with a juvenile. In this species, males tend to dominate over females. – élise Huchard

This research also challenges the notion that power dynamics are solely dictated by physical prowess. In numerous primate societies, female dominance arises not from strength, but from control over reproduction.

“If a female chooses not to mate, a male is powerless to intervene,” Huchard explained. “If females manage breeding, it can serve as a leverage point in their interactions with males.”

While researchers are cautious about extrapolating their results to human behavior, they suggest the findings illuminate the remarkable flexibility of gender roles among our evolutionary relatives.

“We have two close relatives, the chimpanzee and the bonobo. One exhibits male dominance while the other operates predominantly under female leadership,” Huchard noted. “Thus, even prior to our research, we understood that these dynamics are not deterministic.”

The findings indicate that the social hierarchy within primate societies—and possibly humans—is adaptable, shaped by environmental conditions, group composition, mating strategies, and individual relationships. In essence, no single model dictates who holds power.

Read more:

About our experts

Dieter Lukas is an evolutionary biologist specializing in the social systems of both past and present populations, approached from a comparative perspective at the Max Planck Institute for Evolutionary Anthropology. His recent studies challenge fundamental assumptions in human behavioral ecology, revealing that variations in human behavior are likely influenced by similar factors that guide the behaviors of other mammals and birds.

élise Huchard is a researcher at the University of Montpellier in France. Her primary focus is on mammalian social behavior, conducted through comparative analysis, as well as long-term investigations in natural populations. She also serves as the editor-in-chief of the journal Frontiers in Ecology and Evolution.

Source: www.sciencefocus.com

Male lemurs exhibit enlarged testicles in the presence of other males

Posted on by
Reply

Male Verreaux’s Sifaka

Gabriel Bueno

Dominant male lemurs grow more flexible testicles when other males are present, improving their position for successful mating.

In many species, dominant males have larger testes than subordinate males. Increased Testosterone Research has also shown that males of group-living, multi-male species have larger testes than males of group-living, single-male species. Larger testes mean more sperm can be produced, which increases the male’s chances of producing offspring if a female mates with multiple males.

Gabriel Bueno and Rebecca Lewis Researchers at the University of Texas at Austin tested whether this pattern held true within a single population by looking at testicle size in 23-year-old adult men. Verreaux’s sifaka (Propithecus beleaucii) took place outside of the mating season over a 13-year period in Kirindimitea National Park in western Madagascar.

This lemur group is made up of several groups, some with only one male and some with several. As in all lemur societies, the females hold the most social power, but the males also have their own hierarchy. Dominant lemurs have greasy brown spots on their chests from constant scent marking, while subordinate lemurs have clean white bodies.

The researchers found that the testicles of stained males in multi-male groups were on average 103 percent larger than those of clean males from the same groups and 31 percent larger than those of stained males in single-male groups. The stained lemurs in multi-male groups may be producing more testosterone than other lemurs or they may be suppressing the amount of testosterone that clean males can produce, Bueno says.

Stained males living in multi-male groups not only have larger scrotums in absolute terms, but also larger relative to their body size, which Bueno says suggests indicates that dominant males spend more energy competing for sperm when there are other males around.

“The key is that they can make that switch,” Bueno says. Because the dominant male always has the largest testicles, when a dirty male with larger testicles enters the group, the dirty male’s gonads grow. This “highlights how extraordinarily flexible they are and how they adapt to their social environment,” Bueno says.

“It is surprising that males can flexibly adjust their testis size across a range of environments throughout their lives,” he said. Peter Kappeler The researchers, from the University of Göttingen in Germany, added that their findings raise important questions about the potential costs of maintaining large testes: Enlarging them requires energy that cannot be used elsewhere, and likely requires the animal to search for more food.

topic:

Source: www.newscientist.com