The Responses of Ecologically Dissimilar Populations of the Water Snake, Natrix sipedon sipedon to Surface Extracts of Prey Species, With Observations on Feeding and Defense Behaviors

Observations of defensive and feeding behavior of Natrix sipedon were made in the field and in the lab. Crypticity, mimicry of poisonous snakes, striking, production of cloacal secretion and tail autonomy were defensive behaviors discussed. Feeding behaviors discussed were hunting, catching prey and tongue-flicking.

Experiments were performed on the responses of snakes from ecologically dissimilar populations of N. sipedon to surface extracts of local prey species. The populations were: (1) a laboratory-reared litter of ten one-year-old snakes; (2) six wild-caught snakes from Sterchi's fish hatchery in north Knoxville, Tennessee; and (3) six wild-caught and eight newborn snakes (a litter) from the Tremont area of the Great Smoky Mountains National Park. Extracts were made of prey species caught in both areas or obtained in the laboratory. Response scores were combined measure of tongue-flicks and attack latency.

Group one snakes responded significantly more to goldfish (C. auratus), than to any other extract. This species has been their food for one year. Group 2 also responded more the C. auratus than to any other fish extract. The goldfish was abundant at Sterchi's. However, Group 3 responded significantly more to extracts of fish that were caught near Tremont than to C. auratus. That snakes discriminated between different genera of prey was shown. The conclusion was made that wild-caught snakes respond more often to extracts of sympatric prey, presumably because these snakes have had experience eating this prey. Young of the Tremont snakes responded more to extracts of sympatric prey than to C. auratus, but the difference was not significant. This technique can be used, in conjunction with other investigations, to assess ecological relationship in an area.