Researchers studying banded mongooses in Uganda have discovered that these small mammals are able to discriminate between relatives and non-relatives to avoid inbreeding even when mating within their own closely related social group. Inbreeding can be a big problem for social species such as banded mongooses because they grow up in social groups consisting mainly of close relatives. This study is the first to suggest that social animals are able to avoid the costs of inbreeding without relying on un-related mating partners from other social groups.

Dr Jennifer Sanderson, from the University of Exeter, has been observing wild banded mongooses to understand how they avoid the negative aspects of inbreeding. The findings of the 16-year study are published today in the journal Molecular Ecology.

She found that while most social mammals avoid inbreeding by either not breeding or dispersing to a group of non-relatives, male banded mongooses avoid inbreeding by focusing their mating effort towards females within their extended family to which they are least related.

Although the researchers do not yet understand how they avoid inbreeding, the mongooses may use scent, or their highly individual calls, to help them gauge relatedness.

According to Dr Sanderson: "Wild animals are known to use a variety of tactics to avoid the costs associated with inbreeding but most of these tactics involve dispersal or waiting to encounter an unrelated immigrant. Our study has shown that both male and female banded mongooses are able to avoid inbreeding while mating within their family group even in the absence of immigration".

Dr Sanderson collaborated with Dr Hazel Nichols to collect thousands of genetic samples from the Ugandan mongooses which were then analysed at Liverpool John Moores University.

Dr Nichols from Liverpool John Moores University said: "We've used a large number of genetic markers to determine the parents of over 1500 banded mongoose pups. This has allowed us to quantify the occurrence of inbreeding and investigate the tactics used by both male and female banded mongooses to avoid it."