Serpente como presa de serpentes: revisão do hábito ofiófago

Abstract

Snakes are widely distributed throughout the planet, and show great diversity of habits, diet, and morphology. Diet is considered a central factor that influenced the evolution of snakes, since they have adaptations to locate, subjugate and ingest a wide variety of prey. In addition, the type of prey consumed may influence the distribution and abundance of snakes, as well as their daily and seasonal patterns of activity and habitat use. Concerning diet, snakes may be classified as generalists or specialists, preying on several kinds of items, ranging from eggs to large vertebrates. Ophiophagy is widespread and relatively well documented in this group. Most ophiophagous snakes start ingesting the prey head-first, which reduces the resistance offered by the prey, and, consequently, the ingestion time. However, it is noteworthy that there are records of ophiophagous snakes which ingest prey tail-first, as those of the genus Erythrolamprus. Our objective was to review the ophiophagous habit throughout snake families, seeking for phylogenetic and/or ecological pattern. We employed meta-analysis, reviewing scientific articles, databases (e.g. Scopus, Web of Science), academic Google, books, and information of collaborator researchers. We use the following keywords as search engines “diet, dietery, feed, ophiophagy, feeding, ophiophagous”. The ophiophagous habit is widespread in the Alethinophidia, occurring in fourteen out of the twenty-eigh currently recognized families. Among these, the family Elapidae presents the highest index of ophiophagy, corresponding to 35% of the predation events returned in the research. Accordingly, earlier studies corroborated the idea that the common ancestor of the elapids had lizards and snakes as their diet. Such high incidence of ophiophagy in this group is attributed mainly to the morphology of the head. Among the most consumed species, were Erythrolamprus and Atractus, both known for not showing aggressive behavior and for not presenting public health problems. The snakes of these genera have terrestrial and fossorial habits, respectively, and therefore, this high predation in the genus may be associated with the fact that about 78% of the snakes are terrestrial and 13% fossorial. Regarding daily activity, 51% of ophiophagous snakes are nocturnal and 36% are diurnal, showing that these habits influence the type of food consumed, as certain prey may be active only one hour of the day. Once again, we notice a similarity between ophiophagous snakes and Atractus and Erytrolamprus. Our results show how, even a relatively known habit in snakes, is still undersampled. In addition, they indicate important correlations between feeding habits, morphology and use of the environment by these animals.