The toll courtships take on primates.

For many species, lengthy mating seasons are hard on males, studies have shown. They eat less well while pursuing females and suffer bruises from warding off other males.

What about the few primates that, unlike most mammals, breed throughout the year? Previous research had suggested that the brief courtships of these primates-including humans, baboons, and chimpanzees-don't exhaust the males, but a new, more detailed study challenges that view.

Susan C. Alberts of Harvard University and her colleagues studied 15 to 25 baboons in three social groups living in and around Amboseli National Park in southern Kenya. They calculated how far the animals traveled for food and how long they spent eating. When alone, a male travels farther to find food than he does when alongside his female, which needs to eat less. The male spends the same amount of time foraging whether he is courting or not, but he has less time for eating when keeping an eye on his female, the authors report in the June Animal Behaviour. Unlike seasonal breeders, these males had little time between courtships to catch up on their calories, the authors note. Indeed, baboons and other nonseasonal breeders probably spend about the same amount of energy over their lifetime on courtships as the seasonal fellows do, the team speculates.

The group is now investigating whether the amount of food available to the baboons influences how much time they can spend courting, their success rate, and their willingness to pursue less cooperative females, say the authors.