Chicago Garter Snake

Chicago Garter Snake
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Thamnophis
Species:	T. sirtalis
Subspecies:	T. s. semifasciatus
Trinomial name
Thamnophis sirtalis semifasciatus Cope, 1892

The Chicago Garter Snake (Thamnophis sirtalis semifasciatus) is a subspecies of garter snake native to the Chicago region. It was first published by Edward Drinker Cope in 1892, and can be found in the vicinity of rural waterways in northeastern Illinois, such as Piscasaw Creek in Boone County and McHenry County, Illinois.^[1]

Description

Identification

The Illinois Natural History Survey describes the Chicago garter snake as a medium-sized (up to 100 cm total length, including tail) dark brown or black snake with a yellow or gray midback stripe, a yellow stripe on each side, and a gray-green belly with dark spots on the edges of most of the belly scales. The snake's head is usually without parietal light spots. Some individual specimens have red coloring between the side scales.^[1]

One identifying element that distinguishes the Chicago garter snake from other garter subspecies, especially the eastern garter snake (Themnophis sirtalis sirtalis), is that in Thamnophis sirtalis semifasciatus, the snake's side stripe is broken, near the snake's head, into a dashed line by black crossbars.^[1]

Habitat

The Chicago garter snake prefers forest and edge habitats near a body of water. It is a cold-tolerant snake that occasionally emerges from hibernation to bask on warm winter days. The snake emerges from hibernation upon the spring thaw (March or April), and typically mates immediately after emerging from hibernation. The females, like other garter snakes, give birth to a clutch of 15–80 live young; parturition is typically in July through early October. The newborn snakes are 15–20 cm (6–8 in) in total length.^[1]

The Chicago garter snake's typical diet includes fish, amphibians, young birds, and a variety of invertebrates, such as earthworms, slugs, and snails. The snake is often killed by human beings and by a wide variety of predatory vertebrates, especially hawks and owls.^[1]

References

1. ^ ^{a b c d e} "Thamnophis sirtalis - Common Garter Snake". Illinois Natural History Survey. http://www.inhs.illinois.edu/animals_plants/herps/species/th_sirtali.html. Retrieved 2011-02-08.