Graham's crayfish snake (Regina grahamii)

Graham's crayfish snake
IUCN Red List species status – Least Concern LEAST

Top facts

  • Graham’s crayfish snake is distinctive within the Regina genus as it has the lowest proportionate head length relative to body ratio.
  • Graham’s crayfish snake is named after James Duncan Graham who was an American engineer, astronomer and biological collector.
  • The female Graham’s crayfish snake gives birth to live young, rather than laying eggs.
  • As its name suggests, crayfish are the preferred prey item of Graham’s crayfish.
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Graham's crayfish snake fact file

Graham's crayfish snake description

GenusRegina (1)

Graham’s crayfish snake (Regina grahamii) is a medium-sized (2) (4), stout-bodied, brown or olive aquatic snake species (2). There is a yellow stripe on each side of the body which is bordered by thin, dark brown lines, and there may be a faint, tan-coloured line running along the middle of the back (4). The underside of this reptile is cream or light yellow (3) (4) and may have a faint, darker line or row of grey or light brown spots running lengthways along the centre (3) (4).

The male and female Graham’s crayfish snake are similar in appearance, except for the female being slightly larger. The juvenile has a similar colouration to the adult, although the stripe pattern is slightly more distinctive (3).

Maximum length: up to 100 cm (2)
Average male snout-vent length: 54.3 cm (3)
Average female snout-vent length: 59.2 cm (3)
Average male mass: 64.9 g (3)
Average female mass: 116.4 g (3)
Newborn length: 15 - 25 cm (2)

Graham's crayfish snake biology

Graham’s crayfish snake is active between April and early November (4), when it can be found basking on rocks (2) or on tree branches hanging over water (2) (4). When it is not basking, this species is known to take shelter underneath logs, rocks or disused crayfish burrows (4). While hibernating during the winter, Graham’s crayfish snake either excavates its own burrows or utilises those made by crayfish (2). Although this species is usually active during the day, it may become nocturnal during periods of hot weather (4).

The mating season usually occurs between late April and May (2) (3) (4), when small mating balls are formed with one female and many males (3). The average litter of Graham’s crayfish snake contains between 4 and 39 young (3) (4), although around 15 is most common (3), with the female giving birth to live young rather than laying eggs (4). The young are generally born from late July to September (2) (4).

The diet of Graham’s crayfish snake is composed mainly of freshly moulted crayfish (4), although fish and frogs are also taken (2).


Graham's crayfish snake range

Graham’s crayfish snake is endemic to the United States, where it is found from Nebraska in the west to Iowa and Illinois in the east, and to Louisiana and Texas in the south (1).


Graham's crayfish snake habitat

Graham’s crayfish snake is usually found in and around slow-moving ponds, lakes, ditches, swamps and marshes (1) (2) in areas with abundant vegetation (2).


Graham's crayfish snake status

Graham's crayfish snake is classified as Least Concern (LC) on the IUCN Red List (1).

IUCN Red List species status – Least Concern


Graham's crayfish snake threats

Although Graham’s crayfish snake is locally common within its range, many populations have declined due to pollution, acid rain and wetland drainage (1). Individuals of this species are often mistaken for cottonmouths (Agkistrodon piscivorus) (4) which are venomous aquatic snakes that have a similar range to this species (5), meaning that many Graham’s crayfish snakes have been killed by humans under the false belief that they are dangerous (4).


Graham's crayfish snake conservation

There are not known to be any conservation measures currently in place for Graham’s crayfish snake, although this species is known to occur in several protected areas (1). Additionally, this reptile is classified as vulnerable in Arkansas and Oklahoma and as imperiled in Nebraska (3). Additional research into the pressures on this species would be highly beneficial to assess whether any threats are putting Graham’s crayfish snake at risk of extinction (1).


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A species or taxonomic group that is only found in one particular country or geographic area.
A winter survival strategy in which the animal passes the winter in a resting state. This period of inactivity is characterised by specific biological and biochemical changes including lowered blood pressure and respiration rate. In reptiles, this is also known as brumation.
In insects and other arthropods, a stage of growth whereby the hard outer layer of the body (the exoskeleton) is shed and the body becomes larger.
Active at night.


  1. IUCN Red List (April, 2014)
  2. Illinois Natural History Survey - Graham’s crayfish snake (April, 2014)
  3. Gibbons, J.W. and Dorcas, M.E. (2004) North American Watersnakes: a Natural History. University of Oklahoma Press, Norman, Oklahoma.
  4. Missouri Department of Conservation - Graham’s crayfish snake (April, 2014)
  5. IUCN Red List - Agkistrodon piscivorus (April, 2014)

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Graham's crayfish snake  
Graham's crayfish snake

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