BAND-STRUCTURE AND FAILURES OF REPRODUCTIVE SUPPRESSION IN A COOPERATIVELY BREEDING CARNIVORE, THE SLENDER-TAILED MEERKAT (SURICATA-SURICATTA)

The extent to which band structure influences the distribution of bree ding activity is unknown for the slender-tailed meerkat Suricata suric atta, a cooperatively breeding mongoose. Here we present the residence histories of three focal bands monitored over ten band-years in the s outhwestern Kalahari, with less detailed data derived from non-focal b ands for a further 20 band-years. Mean total band size early in the br eeding season was 10, and mean size excluding juveniles was 6.7. Despi te a tendency towards females among juveniles, and males among yearlin gs and adults, sex ratios within each age class did not significantly deviate from unity, but at the population level there were significant ly more adult males than reproductive females. A large proportion (71. 6%) of adult females bred, and failures of reproductive suppression oc curred in 40% of band years. This incidence was high in all years and was not obviously related to environmental conditions. Bands with more than one reproductive female contained significantly more adults and adult females than bands with only a single reproductive female. There was a strong correlation between numbers of reproductive females and numbers of adult females in a band. Most (68%) subordinate females whi ch bred were aged three years or more. Reproductive competition was st rong and there was a negative correlation between numbers of adult fem ales, breeding females or adult males and per capita juvenile producti on. Meerkat bands are unusual among cooperative breeders because many individuals were non-kin and the relative constancy in band size withi n and between years masked a high turnover of membership: all animals of known origin aged three years or older, were immigrants, although p hilopatry was commoner among younger animals. Our data show that meerk ats employ a range of reproductive strategies: bands exhibiting a spec trum of reproductive suppression coexist, and individuals respond to t he opportunities afforded by their social environments.