Alternatively, color might vary among individuals because it is controlled by genes that are under natural selection or neutral evolution. Past researchers have proposed that the color variation on the head and chin is associated with the sex of the individual. Despite significant conservations efforts for this species, little is known about its biology in the field.

Eastern Indigo Snakes (Drymarchon couperi), a federally threatened species, have coloration on the sides of the head and the chin that can vary from black to red or cream. Various forms of natural selection, such as mimicry, crypsis, and species recognition, as well as sexual selection, can influence the evolution of color. Many species exhibit variation in the color of their scales, feathers, or fur. These findings indicate that habitat fragmentation is likely to be the critical factor for species' persistence.īold Colors in a Cryptic Lineage: Do Eastern Indigo Snakes Exhibit Color Dimorphism?ĭeitloff, Jennifer Johnson, Valerie M. Our results indicated that adult eastern indigo snakes have relatively high survival in conservation core areas, but greatly reduced survival in conservation areas along highways and in suburbs. We found a transmitter implantation effect on snake encounter probability, as snakes implanted on a given occasion had a lower encounter probability on the next visit compared with snakes not implanted on the previous occasion. We predicted that male snakes in suburbs would have the lowest annual survival. alive or dead) could not be assessed, we employed a multistate approach to model snake apparent survival and encounter probability of live and dead snakes.

Because of a large number of radio-tracking locations underground for which the state of snakes (i.e. In an effort to estimate snake survival, a total of 103 individuals (59 males, 44 females) were followed using radio-tracking from January 1998 to March 2004 in three landscape types that had increasing levels of habitat fragmentation: (1) conservation cores (2) conservation areas along highways (3) suburbs. The eastern indigo snake (Drymarchon couperi) is a federally listed species, most recently threatened by habitat loss and habitat degradation. Habitat fragmentation effects on annual survival of the federally protected eastern indigo snakeīreininger, D.R.

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