Coppery titi monkeys are extremely loyal to their mates, according to research from the German Primate Center (DPZ). Across an entire study population living in the Amazon lowland rainforest, genetic testing revealed that there was not a single example of infidelity.
“In pair-living mammals, genetic monogamy is extremely rare,” explained the researchers. “One possible reason is that in socially monogamous animals, mate choice can be severely constrained, increasing the risk of inbreeding or pairing with an incompatible or low-quality partner.”
“To escape these constraints, individuals might engage in extra-pair copulations. Alternatively, inbreeding can be avoided by dispersal. However, little is known about the interactions between mating system, mate choice, and dispersal in pair-living mammals.”
Coppery titi monkeys live in small family groups that consist of one male, one female and their offspring, with a single infant typically born each year. The children leave the group when they reach sexual maturity to search for a partner and set up a new territory. The partners maintain a strong relationship, spending day and night in close proximity and grooming each other.
For the investigation, 14 groups of coppery titi monkeys were studied. DNA testing showed that all of the offspring were born to monogamous partners.
In addition, the adult monkeys showed high levels of genetic diversity. “Extra-pair breeding would therefore not have provided a genetic advantage for the animals studied, so that they presumably rather avoided the risks of infidelity, explained Sofya Dolotovskaya, who studied the animals for 14 months of field research as a doctoral student.
“In an undisturbed ecosystem, as at our field station, young coppery titi monkeys obviously migrate far enough from their natal group to find a suitable partner without incurring the risk of inbreeding,” said study co-author Eckhard W. Heymann. “Further studies must show whether genetic monogamy also prevails in other populations of coppery titi monkeys, especially in fragmented habitats”.
The study is published in the journal Scientific Reports.