COS 184-2 - Foraging Cooperation in the Naked Mole-Rat

Background/Question/Methods

Naked mole-rats are one of the only eusocial mammals, and thus are assumed to have group-oriented behavior similar to that of eusocial insects. In the context of foraging, naked mole-rats should sacrifice individual foraging opportunities and subject themselves to increased predation risk for the benefit of the colony. However, unpublished data has suggested that unlike other (less social) rodents, naked mole-rats may be unwilling or unable to share information regarding the location of high-quality food patches. I measured giving-up densities (the amount of food left behind in a patch after a period of foraging) in food patches of varying quality at varying spatial scales and recorded video of all foraging that took place. Individuals were number marked to aid identification. My objectives were to 1) determine If naked successfully mole-rats share information about high quality food patches, 2) to determine if foraging is delegated to a few individuals or more evenly spread among colony members, and 3) to determine if there is a correlation between size (and thus rank) of an individual and time spent foraging.

Results/Conclusions

As hypothesized, naked mole-rats were able to distinguish between low and high-quality food patches when they were close together, and this ability diminished when food patches of different qualities were far apart from each other. This provides further evidence that they are unwilling or unable to share information about food patch quality. Preliminary data suggests that only a few individuals to the bulk of the foraging in naked mole-rat colonies, and these individuals are of intermediate size. This is contrary to my hypothesis that smaller individuals would be doing the majority of the foraging.