Research Training Program

Smithsonian Institution
National Museum of Natural History

PROJECT SUMMARY
1996

Deni Porej
University of Belgrade
Belgrade, Yugoslavia
Thomas H. Fritts, Ph.D.
Department of Vertebrate Zoology
Division of Reptiles and Amphibians
"It was an unique experience in every way. Like a dream come true."

Tail loss in The Brown Tree Snake (Boiga irregularis) on Guam:
Evidence of predation and the effect on growth rates

ABSTRACT
In the years following World War II, a colubrid snake, Boiga irregulars, was introduced on the island of Guam, located north of New Guinea. This native of Northern Australia caused extinction or extirpation of several bird, insectivorous bat and lizard species on the island, and reached densities of 50 snakes/ha. Besides altering the complete ecosystem structure, it also has an impact on many aspects of human activity, especially by causing numerous power outages by contacting power lines, hurting military, commerce and tourist industries. Now the danger exists of the Brown Tree Snake reaching other islands in the region, including Hawaii. Studies done by the National Biological Service are covering all aspects of the snake's ecology, trying to provide information that could be useful in controlling its population and further dispersal. From a theoretical point of view, this phenomenon is a unique opportunity for the study of population dynamics, predator - prey interactions, colonization and ecosystem stability of the islands. The object of this study was to explore possible causes of tail breakage observed on snakes on Guam. These results suggest that tail breakage could be a landmark of an attack on snakes by Coconut Crab (Bogus latro), Hermit Crab (Coenobita spp) and ubiquitous rats. The preliminary analysis on the effect the tail loss has on the growth rates presented in this study suggests the need for caution when constructing growth curves for snakes on Guam, and that the tail loss should not be ignored. These results have opened a whole new area of interest, and have set a good foundation for future studies.

This research was supported by a grant from the Smithsonian Women's Committee.

Letter of Gratitude