Until recently, venom in reptiles was thought to be present in two lineages: Serpentes and Heloderma. Research has now shown that venom evolved only once in reptiles, in a venom clade known as Toxicofera. This has resulted in venoms being...
moreUntil recently, venom in reptiles was thought to be present in two lineages: Serpentes and Heloderma. Research has now shown that venom evolved only once in reptiles, in a venom clade known as Toxicofera. This has resulted in venoms being discovered in many more species within this clade, including monitor lizards, genus Varanus. To date, very little work has been published on the ecological function of venom in monitor lizards. More generally, venom can fulfill four functions: defence, prey capture, aiding digestion, and maintaining oral hygiene through antimicrobial effects. Although more than one function may be served by the venom of any given species, in most cases one of these is more important than others, i.e., the primary function. Previous evidence for prey capture as the primary function of venoms has often used data on wild prey to assist interpretation, and as a result, a compilation of wild monitor lizard diets is presented. Subsequently, speculations on the primary function of Varanus venoms are made and discussed. Although many data are needed to support or refute many of the points discussed, I suggest that an enhancement of digestive function may be an important element of the venom, possibly the primary function in at least some species. The suggestions are made with the aim of encouraging future work to empirically test the hypotheses
which derive from the ideas herein. Only in this way can we hope to further our knowledge on the ecology of venom in reptiles.
