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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Eastern Milksnake
Lampropeltis triangulum
Family: Colubridae
COSEWIC status:- Special Concern
- Special Concern
- Least Concern
Description
The Eastern Milksnake is grey or tan with alternating red or reddish brown blotches that are distinctly outlined in black along its back and sides. The coloration of this species tends to be brighter in juveniles but is still very pronounced in adults. This snake has smooth scales, a white and black chequered belly and usually has a distinct Y- or V-shaped mark on the back of its head. The Eastern Milksnake is a long, narrow snake that can grow to over a metre in length, although most individuals are much smaller.
Similar Species
The Eastern Milksnake may be confused with the Northern Watersnake, Eastern Foxsnake, Eastern Hog-nosed Snake, Massasauga and young Gray Ratsnake. The Northern Watersnake’s patterning consists of horizontal banding rather than blotches and can be very faint on a much darker body. Adult Eastern Foxsnakes have a yellow to light brown body with brown blotches that are not outlined in black (although the blotches of juvenile foxsnakes can have dark edges). The Eastern Hog-nosed Snake has a distinct upturned nose. The Eastern Massasauga is very thick-bodied compared with the long, narrow Eastern Milksnake and usually has a rattle on a blunt tail, a vertical pupil and a triangular head. Juveniles of these and other species look very similar and can be difficult to differentiate.
Distribution
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In Canada, the Eastern Milksnake is limited to southern Quebec and Ontario south of Lake Superior. This species is found throughout the northeastern United States as far south as northern Alabama and west to Minnesota and Iowa.
Habitat
Eastern Milksnakes can be found in a variety of habitats but tend to use open habitats such as rocky outcrops, fields and forest edges. In rural areas this snake may be common, especially around barns where they thrive on the abundant mice. The Eastern Milksnake hibernates underground in rock crevices, mammal burrows or in the foundations of old buildings. Females nest in rotting logs, stumps, vegetation piles, loose sand or the burrows of small mammals.
Biology
Eastern Milksnakes breed in the spring and females lay 8-11 elliptical eggs in the early summer each year, which hatch in 7-10 weeks. Eastern Milksnakes reach maturity after three to four years and individuals may live for more than 20 years. The name of this species is derived from the false belief that it takes milk from cows in barns, which it often inhabits. Eastern Milksnakes cannot drink milk, however, and are attracted to barns by the abundance of mice, the primary prey of this species. It is a semi-constrictor: it seizes prey in its mouth and coils around the prey until it has suffocated. Predators of the Eastern Milksnake include a number of mammal species (including domestic cats) hawks and crows. When threatened, the Eastern Milksnake vibrates its tail and, especially when it comes into contact with dry vegetation, makes a buzzing or “rattling” sound. This behaviour, combined with the snake’s blotchy patterning, causes many people to mistake it for a rattlesnake.
Threats
Human persecution is a significant threat to the Eastern Milksnake. People often kill it on sight, mistaking it for a venomous Massasauga due to its pattern and tendency to vibrate its tail when disturbed. Eastern Milksnakes are also commonly killed on roads, and this mortality may be unsustainable in regions with high road density. Habitat loss due to urbanization and conversion of natural areas to agricultural uses is also a threat to Eastern Milksnake populations in Canada.