Lizard herbivory in a sand dune environment: the diet of Angolosaurus skoogi

Early observations of the feeding habits of Angolosaurus skoogi (Andersson), a 50-120 g lizard inhabiting the almost vegetationless dunes of the northern Namib Desert, indicated that this species was herbivorous. Less than two percent of living lizard species are predominantly herbivorous and these species tend to have a high body mass (>100 g). We therefore analysed fecal pellets of A. skoogi to obtain dietary details of this relatively rare lizard. Eighteen food taxa were identified: 81 percent by mass was composed of vegetable matter, of which 56 percent was an endemic, perennial cucurbit Acanthosicyos horrida. Both spatial and temporal variation in dietary composition were apparent. Ready access to water in the form of A. horrida is postulated to have allowed Angolosaurus to occupy this extreme habitat and to forage on components of the windblown detritus, a food source that would probably not be usable in other circumstances.