California kingsnake

Identification

The California kingsnake is a medium to large constrictor with smooth, shiny scales and round pupils^1,3. Over most of its range it is black or dark brown with 21–44 broad white or pale yellow bands that widen on the lower sides, and the light bands continue across the belly^1,2. Along the coast of southern California, some individuals instead have a single thin pale stripe running down the back^1,2. In parts of Sonora, Mexico, adults may darken to almost plain black¹.

Most adults are about 76–122 cm long, and few exceed 1.2 m^1,2. The largest reported size is about 2 m¹.

Distribution

The California kingsnake lives in the western United States and north-western Mexico¹. Its range covers most of California, south-western Oregon, Nevada, southern Utah, extreme south-western Colorado and much of Arizona, and in Mexico all of Baja California and much of Sonora^1,2. In California it is absent only from the damp redwood belt of the far north-west coast, the north-eastern Great Basin desert and high mountains².

It was once treated as a subspecies of the common kingsnake, Lampropeltis getula, but in 2009 it was recognised as a separate species^1,2. An introduced population lives on Gran Canaria in the Canary Islands, where it was first detected in 1998⁵.

Habitat

This kingsnake lives in a very wide range of habitats, including forest, woodland, chaparral, grassland, marshes, farmland, deserts and brushy suburban areas². It is found from sea level to about 2,160 m in the Sierra Nevada².

Behaviour

The California kingsnake is active by day in cooler weather, and at dawn, dusk and night when it is hot². It lives mainly on the ground and often shelters in rodent burrows and under logs¹⁰. When disturbed it is usually not aggressive, but it may vibrate its tail, hiss, or roll into a ball with its head hidden, sometimes everting its vent^2,3.

Diet

It eats a wide variety of animals, including rodents, lizards and their eggs, snakes, turtle eggs and hatchlings, frogs, salamanders, birds and their eggs². It is well known for eating other snakes, including rattlesnakes, and it is resistant to rattlesnake venom^2,3. Kingsnakes, including this species, squeeze their prey harder than rat snakes of a similar size, which helps them overpower other snakes, even ones larger than themselves⁴.

Reproduction

The California kingsnake lays eggs¹. Mating usually takes place within a few weeks of the snakes leaving their winter shelters, and about six weeks later females lay 3–24 eggs, usually about 8–10². The eggs hatch after six weeks to two months, sooner in warmer conditions².

Venom and medical significance

The California kingsnake has no venom and is not dangerous to people². If it is handled roughly it may bite or release a foul-smelling musk, which are normal defensive behaviours¹⁰. Like other reptiles, kingsnakes can carry Salmonella bacteria, so hands should be washed after touching one or its equipment¹⁰.

Conservation

The California kingsnake is listed as Least Concern on the IUCN Red List, in an assessment published in 2019⁷. It is not on California’s Special Animals List, which suggests no significant conservation concern in the state².

On Gran Canaria, where it is an invasive species, it has caused severe declines in the island’s native reptiles⁶. In invaded areas the Gran Canaria giant lizard was more than 90% less abundant, the Gran Canaria skink more than 80% and Boettger’s wall gecko more than 50%⁶. The Canary Islands and Gran Canaria governments have run control programmes every year since the snake was found⁵.

Similar species

In California, related banded snakes include the California mountain kingsnake (Lampropeltis zonata), the western long-nosed snake and the Mojave shovel-nosed snake². The California kingsnake usually has no red, only black or brown with white or pale yellow bands¹. Red-ringed harmless snakes such as milksnakes are often confused with coral snakes: in US coral snakes the red rings touch yellow, while in these harmless snakes the red touches black⁸. That rule, and the rhyme “red touches yellow, kills a fellow; red touches black, venom lack”, only works for coral snakes in the United States, because some coral snakes in Mexico, Central America and South America have red rings touching white or even black⁸. These differences are not a safe basis for handling any snake. Keep your distance from every snake you cannot identify.

In captivity

The California kingsnake is harmless and has become popular as a pet⁹. Kingsnakes can live for more than 20 years in captivity, and the RSPCA advises keeping them singly, because they eat other snakes and may attack or even eat each other¹⁰. Escaped or released pets are the presumed source of the invasive population on Gran Canaria, so a pet kingsnake must never be let go⁹.