The Burrowing Ecology of the Sand Lizard, Uma notata

Abstract

temperature. They do not bury deep enough to avoid the highest temperatures of midsummer; instead they emerge and seek shade on the surface. When escaping from predators, sand lizards are unselective regarding burying sites. They are more selective in their nocturnal retreat in which they bury at the windward end of small accretion dunes. In laboratory choice experiments lizards preferred sand from the windward ends of these dunes to coarser or finer sand. The branches and leaves of partially buried shrubs may protect the lizards from predators and reduce the pressure of the overlying sand. Field observations suggest that sand lizards are less plentiful in areas of coarse sand or sand containing a large admixture of silt. In the laboratory, lizards avoided burying in such substrates. Uma is an inefficient burrower compared to some Old World arenicolous lizards. Its adaptations specifically for burrowing are largely behavioral. The morphological features which are adaptive for its burrowing behavior are characteristic of the entire Uma-Callisaurus-Holbrookia stock.