And just as Albery found for the red deer, this isn’t because older macaques have lost more friends or because macaques with fewer friends live longer. “On the contrary,” says Brent.

"You might see 100 animals in one evening. "You can sit in a stand and see red deer, which have massive antlers. The axis deer are beautiful. They can get up to 300 pounds.

Red deer, Cervus elaphus, exhibit such a complex signaling system. During the mating season, males strongly defend a group of females, yet fighting among males is relatively uncommon.