Lampropeltis triangulum, commonly known as the milk snake or milksnake, is a species of kingsnake; 24 subspecies are currently recognized. Lampropeltis elapsoides, the scarlet kingsnake, was formerly classified as the subspecies L. t. elapsoides, but is now recognized as a distinct species.The subspecies have strikingly different appearances, and many of them have their own common names. Some authorities suggest that this species could be split into several separate species. They are not venomous to humans.
Milk snakes commonly exceed 60 cm (24 in) in total length (including tail), with very large specimens known to reach total lengths of 120 to 132 cm (47 to 52 in).They appear to be one of the smaller species of the kingsnake genus, as adults in the wild apparently average from 38 to 225 g (1.3 to 7.9 oz) in North America and most typically do not exceed a total length of 90 cm (35 in). However, unusually large milk snakes can become rather bulkier than average-sized adults and potentially weigh up to 750 to 1,400 g (1.65 to 3.09 lb), though high weights as such are generally reported from captivity. Males typically are larger than females in maturity, although females can be bulkier than males similar in length, as well. Generally more tropical populations, from Mexico and further south, reach larger adult sizes than milk snakes living in the temperate zones. They have smooth and shiny scalesand their typical color pattern is alternating bands of red-black-yellow or white-black-red. However, red blotches instead of bands are seen in some populations. Some milk snakes have a striking resemblance to coral snakes, in Batesian mimicry, which likely scares away potential predators. Both milk snakes and coral snakes possess transverse bands of red, black, and yellow. Experts now recognize that common mnemonics that people use to distinguish between the deadly coral snake and the harmless milk snake are not 100% reliable. Some coral snakes do not have the typical banding colors or patterns.