Dietary Habits and Reproductive Biology of Typhlopid Snakes from Southern Africa

Abstract

We studied diets, sexual dimorphism, and reproductive biology of six taxa of poorly known African blindsnakes (Rhinotyphlops lalandei, Rana mucruso, Rana schlegelii petersii, Rana schlegelii schlegelii, Typhlops bibronii, and Typhlops fornasinii) by dissection of 649 preserved museum specimens. Females matured at larger sizes than conspecific males, and the degree of sexual size dimorphism was most extreme in the large heavy-bodied R. s. schlegelii. Reproduction was highly seasonal in temperate-zone T. bibronii and R. lalandei, with vitellogenesis in spring, oviposition in late summer, and hatching in autumn. All species were oviparous, with mean clutch sizes of four to 25 eggs. Clutch sizes were strongly correlated with maternal body size in T. bibronii and R. lalandei. African Rhinotyphlops and Typhlops fed mainly on larvae and pupae of ants (88-97% of prey items for five of the six species), but adult termites were also eaten. Only R. mucruso fed on termites to a significant degree (38% of prey items). All species fed infrequently on large numbers of small prey (mean number of prey per stomach = 80.4, range 1-927 items). Remarkably, although they attain almost 1 m in length, the world's largest blindsnakes, R. schlegelii and R. mucruso, fed on relatively small termites and ant brood. Collectively, our data show that typhlopid snakes have remarkably conservative diets, supporting the idea that the peculiar skull morphology of the Typhlopidae is an adaptation to feeding on small, clumped, immobile prey. Our findings support the hypothesis that the binge-feeding strategy of typhlopid snakes (rapid ingestion of prey, low feeding frequency; and large meal size) evolved to minimize the time spent inside ant nests and, thus, to reduce the risk of prey-inflicted injuries.