What keeps couples together

In mammals, pair bonds are very rare, one of the few exceptions being the red titi monkeys of South America. These relatively small tree dwellers live in pairs or small family groups and are characterized by the fact that the males take intensive care of their offspring. A team of researchers from the German Primate Center—Leibniz Institute for Primate Research has now investigated how pair relationships work in titi monkeys. Their results support the so-called "male-services hypothesis": Males provide a useful service by taking more care of the offspring and defending the territory against intruders, while the females are more involved in relationship management and, for example, seek the proximity of their partner more often. The findings are published in Royal Society Open Science.