The Food Habits and Feeding Behavior of New World Coral Snakes

Abstract

This thesis considers the food habits and feeding behavior of New World venomous coral snakes, with emphasis on Micrurus fulvius a species that is found in the southeastern United States and northern Mexico. Literature records and the stomach contents of preserved specimens demonstrate that M. fuIvius of all sizes are specialized tertiary consumers. In Texas, they feed mostly on several species of small, secretive colubrid snakes and on skinks of the genera Eumeces and Leiolopisma. Other kinds of lizards and the young of large colubrid and viperid snakes make up the remainder of their prey. Geographic and seasonal variations in the diet ref lect the distribution and availability of particular prey species. The data from other parts of the range do not show differences from the pattern observed in Texas. A preliminary ethogram f or Micrurus fulvius includes 26 action patterns and two orienting movements, and many of these elements are used in feeding behavior. Coral snakes use stereotyped searching movements to find food in litter and to follow prey trailso Visual and chemical stimuli elicit attack, and the prey is held until it is immobilized by the venom. Pre-ingestion movements are inhibited by the prey's struggles and directed by scale overlap. Swallowing is head first, and includes movements of the entire head of the coral snake as well as individual jaw elements. The feeding behavior is interpreted as being intermediate between a simple colubrid method and the highly specialized viperid type. Data are presented on the food habits of 26 other New World elapids. They are known to eat onycophorans, eels, caecilians, amphisbaenians, lizards, and snakes. The feeding and M® distans behavior of Micruroides is similar to that of M.

euryxanthus , Micrurus corallinus fulvius. Micrurus frontalis and perhaps M. 1emniscatus bite, release, and relocate prey prior to swallowing, but the reason for this apparent innovation is unknown. Morphological, behavioral, and ecological similarities between Old and New World coral snakes may ref lect the phylogeny and zoogeography of the snakes or represent convergence and equivalence. It is suggested that sympatry among New World species might be uncormon or accompanied by size differences.