African clawless otters, spotted-necked otters, and water mongooses all call the same Highveld rivers home, but new MRI research, led by Michael Somers, Sonica Grünschloss, Elréze Scott, André Ganswindt, and Mmatsawela Ramahlo, reveals how these species manage to share this space. The team provides the first dietary assessment of these three carnivores coexisting in a Highveld grassland river system.

Analyzing scat samples collected over two years, the team found that freshwater crabs dominated the diet of all three species, resulting in high trophic overlap. Despite this, coexistence appears to be maintained through differences in dietary breadth and seasonal flexibility, with water mongooses foraging more broadly on land, while African clawless otters increased fish consumption in winter.

These findings highlight the importance of healthy riparian ecosystems. Freshwater crabs and fish, which underpin all three species' diets, depend on thriving river habitats, making their conservation inseparable from the health of the rivers themselves.

You can read the full research paper in the IUCN Otter Specialist Group Bulletin here.