Scent-marking behavior of the southern giant pouched rat (Cricetomys ansorgei)

Abstract

Southern giant pouched rats (Cricetomys spp.) are large rodents in the family Nesomyidae, native to sub-Saharan Africa, that are best known for their olfactory abilities. In fact, because of their acute olfactory abilities, they are used to detect explosives such as landmines. Understanding the natural scent-marking behaviors of animals in this family seems particularly relevant considering the olfactory nature of biodetection and the importance of olfactory communication among rodents in general. For many rodent species, individuals use scent marking to communicate social information to conspecifics. Countermarking (i.e., depositing scent marks either on top of or adjacent to preexisting scent marks of conspecifics) is a primary way rodents communicate information to conspecifics, and countermarks can serve as both intra- and intersexual signals. We presented male southern giant pouched rats (Cricetomys ansorgei) with male urine marks in novel and familiar environments to determine how and where these animals might countermark. A subset of male pouched rats used urine, anogenital, or cheek rubbing to mark adjacent to the preexisting mark in the novel environment only. No males marked in a familiar environment. We suggest that males countermark adjacent to existing marks in novel environments to advertise individual identity to conspecifics while preserving the identity of others.