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Graham's Crayfish Snake - Regina grahamii PDF Print E-mail
 A Field Guide to Amphibians and Reptiles of Iowa


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PROTECTED. It is illegal to kill or collect this species by law in Iowa. Crayfish snakes are rather secretive making it difficult to determine their distribution in Iowa. They are a species of special concern and we are especially looking for reports from northern and central Iowa. Any reports of this snake are appreciated, however.

Graham's Crayfish Snake, Regina grahamii, head, from Louisa County, Iowa


The Graham's crayfish snake is a medium sized Iowa snake measuring 18 to 28 inches in length Conant and Collins, 1998). It is non venomous . The ground color is brown or gray. Sometimes there is a faint light middorsal stripe. The lateral stripes are conspicuous and are cream, white, tan, or light yellow and are located from the belly up to the fourth scale row. There is a thin black stripe that zig zags along the edge of the ventral scales. The belly is the same color as the lateral stripes and is unmarked, except for a row of dark dots down the center in rare specimens.

The labial scales are the same color as the belly and unmarked. The scales are keeled and the anal plate is divided. Both garter snakes and ribbon snakes have a bright middorsal stripe and a single anal plate. Young Graham's crayfish snakes resemble adults, but may have yellow labials and stripes and a brighter dorsal stripe.

Graham's Crayfish Snake, Regina grahamii, from Louisa County, Iowa

There is a unique melanistic variation of the Graham's crayfish snake reported by Guthrie (1928) from central Iowa. These specimens are brown or black above and dark below. These have been found recently in Iowa.


There are no subspecies of the Graham's crayfish snake, Regina grahamii, recognized.



The Graham's crayfish snake is found across southern and central Iowa with a few scattered records in northern Iowa. More searches may yield additional northern populations. This snake has been declining due to the draining of marshes.


Graham's crayfish snakes inhabit ponds, sloughs, marshes, and slow muddy ditches in prairies or woodlands.


The Graham's crayfish snake is a rather odd snake. It is often grouped in with water snakes, Nerodia, but actually differs from them in many ways. It is diurnal and basks during spring and sometimes fall, but in the summer it is secretive. I am unsure if most specimens become nocturnal during this time, but I have observed specimens in Fremont County crossing the road at night on June 1. Interestingly, the night before I observed a crayfish crawling across the same road.

Graham's Crayfish Snake, Regina grahamii, from Fremont County, Iowa

They are more secretive than either water or garter snakes, which live in the same areas. Graham's crayfish snakes hide under rocks, logs, and other debris at the waters edge and also spend much time in crayfish burrows. These snakes are not aggressive (another characteristic not shared by water snakes). When picked up, they merely flail about and release a little musk. They flatten themselves out, but usually do not strike. I have seen one make short spasmodic flails after being placed on the ground.

Graham's Crayfish Snake, Regina grahamii, neonate shedding, from Louisa County, Iowa

They are active from April to October and spend their winters underground, usually in crayfish burrows (Collins, 1982; Johnson, 1992; Smith, 1961). They breed in spring. There are several reports of many males courting one female at once. The female gives birth to 4 - 35 young in September. I found a female in Louisa County giving birth on September 18.


Graham's Crayfish Snake, Regina grahamii, venter, from Fremont County, Iowa

The Graham's crayfish snake feeds chiefly upon crayfish, especially recently molted crayfish. They are also reported to eat fish and amphibians. They are difficult to keep; specimens usually refuse all food and develop skin lesions easily (Guthrie, 1928; Johnson, 1992; Rossi and Rossi, 1995).

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