Survival of the loudest… for howler monkeys at least
Research by the Whitley Wildlife Conservation Trust and the University of Exeter has shown that the howler monkeys who call most often breed more. And the discovery could help zoos improve the way they care for the species.
Holly Farmer is assistant research officer at the Trust, which runs Paignton Zoo, Living Coasts in Torquay and Newquay Zoo in Cornwall. Holly outlines her findings in a paper to be published in Applied Animal Behaviour Science: “We have found that females who hear males calling breed more and that males who howl more breed more. In zoos, the more often adult males howl, the more likely they are to breed.”
The howler monkey Alouatta caraya is the loudest animal in the Americas – apart from human beings, perhaps. The long call of the male has been recorded at 90 decibels and heard over two kilometres (more than one mile) away. Holly, who has just been awarded her Psychology PhD. by the University of Exeter, has spent time in Argentina studying the species. Until now, breeding in zoos has been poor – but Holly’s research could help to change that.
“In the wild, females are attracted to dominant males who lead the howling. Males who howl more have an increased chance of reproductive success – we think that a similar thing is happening in zoos. Howling may display the fitness of males and maintain social relations.”