An Investigation of Sibling Recognition in a Solitary Sciurid, Townsend's Chipmunk, Tamias Townsendii

Abstract

Abstract We tested juvenile Townsend's chipmunks (Tamias townsendii) to determine whether 1) they could distinguish kin from non-kin and 2) to assess if this ability was based on familiarity or on genetic relatedness. Seventy-three pups between the ages of 55-62 days were observed in 68 pairwise tests. The frequencies (number/trial) and durations (length in seconds) of 8 behaviors as well as the mean distance between pups were recorded in 10 min. trials. Analyses indicated that frequencies of behaviors varied depending on relatedness (related/unrelated) and familiarity (familiar/unfamiliar) but durations of behaviors did not. Pups discriminated between familiar and unfamiliar animals in the frequency of contacts, and the occurrence of attacks and chases. Pups discriminated between animals on the basis of relatedness in the occurrence of chasing. Both relatedness and familiarity played a role in the frequency of sniffing and grooming and in the mean distance between pups, as shown by the significant interaction between familiarity and relatedness in 2-way ANOVAs. The sex composition of pairs (male-male, male-female or female-female) influenced the mean distance between pups. We can only speculate on the functions of kin recognition in Townsend's chipmunk. It may enable animals to selectively direct nepotistic behavior toward kin or facilitate optimal outbreeding.