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Tail autotomy is part of the defensive strategy of the common garter snake (Thamnophis sirtalis), with the greatest frequency in adult females because their mass facilitates breakage. If garter snakes are held by the tail, they rotate the body with a whirling motion that quickly gains momentum and snaps off the tail (Fitch 1965, 1999). In the present report I explore further the topic of tail breakage in garter snakes, comparing the incidence of breaks in the sexes, and in adults vs. young (Tables 1-4).
Methods and Materials.-The records used in this study were gathered during the course of ecological studies on the Fitch Natural History Reservation (FNHR). Only records obtained during the decade of the 1990's (1828 in all) were used. The ratio of those with tail breaks vs. those with intact tails is noted. Two sets of figures were used and compared. In the larger set every capture was included, with the result that some individuals, those recaptured several times, were overrepresented. In the second sample each individual was tallied only once-at its first capture. However, this data set excluded many records of older snakes that were most likely to have broken tails. On a few occasions I accidentally broke a tail in handling a snake, but the vast majority of breaks are believed to have resulted from the attacks of natural predators such as the coyote (Canis latrans), striped skunk (Mephitis mephitis), raccoon (Procyon lotor), opossum (Didelphis virginiana), redtailed hawk (Buteo jamaicensis), and great blue heron (Ardea herodias). In the tables, males of...