Eastern indigo snake | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Colubridae |
Genus: | Drymarchon |
Species: | D. couperi |
Binomial name | |
Drymarchon couperi (Holbrook, 1842) | |
Synonyms [4] | |
The eastern indigo snake (Drymarchon couperi) is a species of large, non-venomous snake in the family Colubridae. Native to the southeastern United States, it is the longest native snake species in the country. [5]
The eastern indigo snake was first described by John Edwards Holbrook in 1842. For many years the genus Drymarchon was considered monotypic with one species, Drymarchon corais, with 12 subspecies, until the early 1990s when Drymarchon corais couperi was elevated to full species status according to the Society for the Study of Amphibians and Reptiles, in their official names list.
The generic name, Drymarchon, roughly translates to "lord of the forest". It is composed of the Greek words drymos (Δρυμός), meaning "forest", and archon (ἄρχων), meaning "lord" or "ruler".
The specific name is a latinization of the surname of American planter James Hamilton Couper (1794–1866). [6] Couper brought Holbrook the type specimen from south of the Altamaha River in Wayne County, Georgia.
The eastern indigo snake has a number of common names including indigo snake, blue indigo snake, black snake, blue gopher snake, and blue bull snake.
The eastern indigo snake has uniform blue-black dorsal scales, with some specimens having a reddish-orange to tan color on the throat, cheeks, and chin. This snake received its common name from the glossy iridescent dorsal and ventral scales which can be seen as blackish-purple in bright light. This smooth-scaled snake is considered to be the longest native snake species in the United States. [5] The longest recorded specimen measured 2.8 m (9.2 ft) in total length (including tail). Unlike many snakes, mature male indigo snakes are slightly larger than females. This is thought to be due to intraspecies competition and combat with the males. [7] A typical mature male measures 1.2–2.36 m (3.9–7.7 ft) in total length, with a reported average of 1.58 m (5.2 ft), and weighs 0.72–4.5 kg (1.6–9.9 lb), reportedly averaging 2.2 kg (4.9 lb). Meanwhile, a mature female typically measures around 1.1–2 m (3.6–6.6 ft) in total length, averaging 1.38 m (4.5 ft), and weighs 0.55–2.7 kg (1.2–6.0 lb), averaging 1.5 kg (3.3 lb). [8] [9] Specimens over 2.6 m (8.5 ft) can weigh up to 5 kg (11 lb). [10] Although the eastern indigo snake is similar in average body mass, extremely large specimens of the bulky, sympatric venomous eastern diamondback rattlesnake can outweigh it. [11]
The eastern indigo snake inhabits areas from far southwestern South Carolina through Florida, and west to southern Alabama and southeastern Mississippi. Their historic range extended into Louisiana. [12] A related species, the Texas indigo snake (Drymarchon melanurus erebennus), is found in southern Texas and Mexico. [13]
Because of habitat loss, the eastern indigo snake is listed as a federally threatened species in Georgia and Florida. [14] In 2012 the Alabama Department of Conservation and Natural Resources had listed the species as possibly extirpated within the state. [15] A reintroduction program has shown initial signs of success, with an individual sighted in March 2022. [16]
The eastern indigo snake was largely eliminated from northern Florida due to habitat loss and fragmentation. A restoration program is currently underway at Apalachicola Bluffs and Ravines Preserve (ABRP) in northern Florida. The eastern indigo snake was last observed at ABRP in 1982, until 2017 when 12 snakes were released as part of the program. Twenty more snakes were released in 2018, and another 15 (10 female and 5 male) in 2019. The 10-year program is a collaborative effort between the Florida Fish and Wildlife Conservation Commission and private partners. [17]
NatureServe considers the species to be Vulnerable. [18]
Another issue the eastern indigo snake is facing would be dealing with infections due to the snake fungal disease (Ophidiomyces ophiodiicola). [19] This fungus infects the dermal layer of snake skin, causing a variety of lesions that commonly manifest on the head and near the vent. [19]
The eastern indigo snake frequents flatwoods, hammocks, dry glades, stream bottoms, cane fields, riparian thickets, and high ground with well-drained, sandy soils. [13] In Georgia, the eastern indigo snake prefers excessively drained, deep sandy soils along major streams, as well as xeric sandridge habitats. [20] [21] In the northern parts range is restricted to sandhills and require Gopher Tortoise burrows during colder seasons [22] Xeric slash pine plantations seem to be preferred over undisturbed longleaf pine habitats. [23] Habitat selection varies seasonally. From December to April, eastern indigo snakes prefer sandhill habitats; from May to July the snakes shift from winter dens to summer territories; from August through November they are located more frequently in shady creek bottoms than during other seasons. [24] In a study in Georgia, winter sightings generally occurred on sandhills, in association with gopher tortoise (Gopherus polyphemus) burrows. [25] These burrows can be used as cover from predators, fires, or extreme temperatures that may come through the area. [26]
The eastern indigo snake is most abundant in the sandhill plant communities of Florida and Georgia. These communities are primarily scrub oak-longleaf pine ( Pinus palustris ) with occasional live oak ( Quercus virginiana ), laurel oak ( Q. laurifolia ), Chapman's oak ( Q. chapmanii ), and myrtle oak ( Q. myrtifolia ). Other communities include longleaf pine-turkey oak ( Q. laevis ), slash pine-scrub oak ( Pinus elliottii ), pine flatwoods, and pine-mesic hardwoods. [20]
Because the cover requirements of eastern indigo snakes change seasonally, maintaining corridors that link the different habitats used is important. From the spring through fall snakes must be able to travel from sandhill communities and upland pine-hardwood communities to creek bottoms and agricultural fields. [24] In winter, indigo snakes den in gopher tortoise burrows, which are usually found in open pine forests with dense herbaceous understories. [23] Burrows need to be in areas where there is no flooding. Eastern indigo snakes heavily use debris piles left from site-preparation operations on tree plantations. [23] These piles are often destroyed for cosmetic reasons but should be left intact because they provide important hiding cover for both the snake and its prey. Summer home ranges for the indigo snake can be as large as 273 acres (110 hectares). [24]
The eastern indigo snake is carnivorous, like all snakes, and will eat any other small animal it can overpower. It has been known to kill some of its prey by pressing the prey against nearby burrow walls. [27] Captive specimens are frequently fed dead items to prevent injury to the snake from this violent method of subduing its prey. Chemosensory studies with mice ( Mus musculus ) have shown that D. couperi responds with significantly elevated rates of tongue flicking and investigation towards visual cues of prey, and not volatile chemical cues. [28] Its diet has been known to include other snakes (ophiophagy), including venomous ones, as it is immune to the venom of the North American rattlesnakes. The eastern indigo snake also eats turtles, lizards, frogs, toads, fish, a variety of small birds and mammals, and eggs. [13] [23] [29]
As defensive behavior the eastern indigo snake vertically flattens its neck, hisses, and vibrates its tail. If picked up, it seldom bites. [30]
It often will cohabit with gopher tortoises in their burrows, although it will settle for armadillo holes, hollow logs, and debris piles when gopher tortoise burrows can't be found. Hunters, hoping to flush out rattlesnakes, often wind up accidentally killing indigo snakes when they illegally pour gasoline into the burrows of gopher tortoises (a practice referred to as "gassing"), even though the tortoises themselves are endangered and protected.[ citation needed ]
As an apex predator, indigo snakes have no natural predators. Instead, humans represent the biggest threat to the eastern indigo snake. Highway fatalities, wanton killings, and overcollection for the pet trade adversely affect indigo snake populations. Snakes are taken illegally from the wild for the pet trade. Eastern indigo snakes are sometimes "gassed" in their burrows by rattlesnake hunters. [20] Along with infrastructure and pet trade, indigo snake populations are drastically declining due to habitat fragmentation. The eastern indigo snake's decline is correlated with the gopher tortoise decline as well since they utilize their burrows for brumation.
The eastern indigo snake is oviparous. [31] The eggs are 75–100 mm (3–4 in) long by 27–32 millimetres (1–1+1⁄4 in) wide. Females will lay a single clutch of 4-14 eggs from late April through early June. [32] The hatchlings are 600–700 millimetres (23+1⁄2–27+1⁄2 in) long. [33] Eastern indigo snakes are often referred to as late maturing colubrids; they usually do not reach maturity until they are 3 to 5 years old and around 5 to 6 feet in length. Female eastern indigo snakes have the ability to retain live sperm for long periods, potentially over 4 years. Thus, females are able to choose when to release the sperm to fertilize the eggs. [34] Mating season is at a peak from November to January but can occur from October through March. [35]
Due to its generally docile nature and appearance, some people find the eastern indigo snake to be a desirable pet, although its protected status can make owning one, depending on location, illegal without a permit. Only a few states require permits to own an eastern indigo snake, but a federal permit is required to buy one from out of state anywhere in the US. The permit costs $100; information about obtaining one can be found by doing a web search. Most states allow unrestricted in-state sales. To thrive in captivity, this snake requires a larger enclosure than most species do, preferably with something to climb on.
One notable owner of a pet eastern indigo snake was gonzo journalist Hunter S. Thompson during the time he wrote his Hell's Angels book. One evening, about 1966, he left his snake - with a mouse to eat - in a cardboard box in the Random House editor's office, but the mouse gnawed through the box and both animals escaped. The snake was subsequently beaten to death by the night watchman, which still caused Thompson great anguish several years later, and was his justification for sending his - often excessive - room service bills to Random House. [36]
This article incorporates public domain material from Drymarchon couperi . United States Department of Agriculture.
Pantherophis obsoletus, also known commonly as the western rat snake, black rat snake, pilot black snake, or simply black snake, is a nonvenomous species of snake in the family Colubridae. The species is native to central North America. There are no subspecies that are recognized as being valid. Its color variations include the Texas rat snake. Along with other snakes of the eastern United States, like the eastern indigo snake and the eastern racer, it is called “black snake”.
Agkistrodon piscivorus is a species of venomous snake, a pit viper in the subfamily Crotalinae of the family Viperidae. It is one of the world's few semiaquatic vipers, and is native to the Southeastern United States. As an adult, it is large and capable of delivering a painful and potentially fatal bite. When threatened, it may respond by coiling its body and displaying its fangs. Individuals may bite when feeling threatened or being handled in any way. It tends to be found in or near water, particularly in slow-moving and shallow lakes, streams, and marshes. It is a capable swimmer, and like several species of snakes, is known to occasionally enter bays and estuaries and swim between barrier islands and the mainland.
Drymarchon is a genus of large nonvenomous colubrid snakes, commonly known as indigo snakes or cribos, found in the Southeastern United States, Mexico, Central America, and South America.
The eastern diamondback rattlesnake is a species of pit viper in the family Viperidae. The species is endemic to the Southeastern United States. It is one of the heaviest venomous snakes in the Americas and the largest rattlesnake. No subspecies are recognized.
Masticophis flagellum is a species of nonvenomous colubrid snake, commonly referred to as the coachwhip or the whip snake, which is endemic to the United States and Mexico. Six subspecies are recognized, including the nominotypical subspecies.
The gopher tortoise is a species of tortoise in the family Testudinidae. The species is native to the southeastern United States. The gopher tortoise is seen as a keystone species because it digs burrows that provide shelter for at least 360 other animal species. G. polyphemus is threatened by predation and habitat destruction. Habitat degradation is the primary reason that the gopher tortoise is listed as vulnerable on the IUCN Red List, but they are considered threatened in some states while they are endangered in others.
The eastern hog-nosed snake, is a species of mildly venomous rear-fanged snake in the family Colubridae. The venom is specifically adapted to amphibian prey and is harmless to humans. However, some people may have an allergic reaction, and experience local swelling and other symptoms. The species is endemic to North America. There are no subspecies that are recognized as being valid. This species prefers habitats with sandy soils and a combination of grass fields and forest edges. They come in many different colorations and have the identifiable upturned "snout". They can be found in captivity but are a relatively difficult species to keep due to a specialized diet of toads. As with other Heterodon species, they have a distinctive threat reaction of first bluffing by striking with a closed mouth and then pretending to die if this fails to deter the threat.
Cemophora coccinea, commonly known as the scarlet snake, is a species of nonvenomous snake in the family Colubridae. The species is native to the southeastern United States. There are two subspecies of C. coccinea that are recognized as being valid. The Texas scarlet snake was previously considered a subspecies.
Sistrurus miliarius, commonly called the pygmy rattlesnake, is a species of venomous snake in the subfamily Crotalinae of the family Viperidae. The species is endemic to the Southeastern United States. Three subspecies are currently recognized.
The Florida cottonmouth is a species of venomous snake, a pit viper in the subfamily Crotalinae of the family Viperidae. The species is endemic to the United States, where it occurs in southern Georgia and the Florida peninsula in nearly every type of wetlands in the region, including brackish water and offshore islands. However, it is not entirely dependent on water and is occasionally encountered as far as a mile from surface water. Agkistrodon conanti venom is very hemolytic and known to cause relatively extensive necrosis compared to many snake venoms, and can sometimes be lethal with a 17% mortality rate. It is often confused with harmless watersnakes (Nerodia) and other semi-aquatic species with which it shares its habitat.
The mud snake is a species of nonvenomous, semiaquatic, colubrid snake endemic to the southeastern United States.
The Atlantic Plain is one of eight distinct physiographic divisions of the contiguous United States. Using the USGS physiographic classification system, the Atlantic Plain division comprises two provinces and six sections. The Coastal Plain province is differentiated from the Continental Shelf province simply based on the portion of the land mass above and below sea level.
Pituophis melanoleucus, commonly known as the eastern pine snake, is a species of nonvenomous snake in the family Colubridae. The species is endemic to the eastern United States. Three subspecies are currently recognized as being valid.
The unicolor cribo is a Central American subspecies of the cribo snakes. The eastern indigo snake, Drymarchon corais couperi is another subspecies of this genus. Until recently the unicolor cribo was considered a subspecies of the same species as the indigo snake Drymarchon corais unicolor.
The gopher frog is a species of frog in the family Ranidae, endemic to the south-eastern United States. It primarily inhabits the threatened sandhill communities, flatwoods, and scrub in the Atlantic coastal plain, where it is usually found near ponds.
The Florida crowned snake is a species of colubrid snake found in Florida and Georgia. It is a small, slender, non-venomous snake that is rarely seen. The species is commonly found in north and central Florida, and is most often associated with sandy habitats.
The indigo snake, also known as the yellow-tail cribo, is a species of snake in the family Colubridae. This large colubrid snake is nonvenomous.
Florida hosts many types of fauna. From coral reefs of the Florida Keys to the cypress swamps of the Panhandle, the state's diverse habitats are home to a variety of wildlife. Florida is among the top five states in terms of endemic species. There are over 700 terrestrial animals, 200 freshwater fish species, 1,000 marine fish and thousands of terrestrial insects and other invertebrates that inhabit the state. Florida's peninsular geography spans from subtropical to tropical zones, which, combined with its distinctive geology and climate, contribute to habitat diversity and an array of species. The native wildlife that exists in the state are of temperate and tropical origin.