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The Black Ratsnake – Notes and Recent Classification Changes

The black ratsnake, Elaphe alleganiensis, found throughout much of the eastern half of North America (even in NYC, on occasion, and its suburbs), is a pet trade staple. Hobbyists have developed a number of unique color morphs, including albino individuals, and frequently hybridize this snake with related species. Since so much is known of its natural history and captive care, I thought I would note here some recent changes regarding its relationships to similar snakes.

The taxonomy of the genus Elaphe is confusing due to a wide variation in the appearance of individuals of the same species, and to the fact that the various species and subspecies inter-breed where their ranges overlap (one reason for the ease in creating different color phases in captivity). Most snake enthusiasts grew up knowing the black ratsnake as Elaphe obsoleta, but that name is a now assigned to the Western ratsnake, with the black ratsnake being re-named as E. alleganiensis. At least 11 species of snake of the genus Elaphe are found throughout North America.

To add to the confusion, black ratsnakes living from North Carolina through the Florida Keys vary greatly in appearance from northern populations, being various shades of yellow and orange in color instead of black. Formerly classified as distinct subspecies, known as Everglades ratsnakes and yellow ratsnakes – both also quite popular in the pet trade – they are now considered to be merely local color variations of the black ratsnake.

The black ratsnake frequently shares hibernation dens with rattlesnakes and copperheads. In some parts of the country it is known as the “pilot blacksnake” or “rattlesnake pilot”, in the mistaken belief that it guides rattlesnakes to their winter retreats. The largest individual on record measured 8 ½ feet long.


The latest information concerning changes in reptile classification and taxonomy is available at the website of the American Museum of Natural History’s herpetology department:


  1. avatar

    Frank. Just out of curiosity. Every where I have looked on the internet the snake eggs are all bare and left uncovered. The twelve that I found were between two bales of cow hay that each weigh close to 500 pounds and two feet from the outside of the round bales towards the center. They were not out in the open. We value our space in the mountains and the bales were crushed together. How important is it that I keep them covered with the moist, rotted straw? Or can I leave them out in the open air exposed only to the elements of the terrarium. They were clutched together in two feet thick of hay. I just want these bad boys to hatch and live the good life eating rats and mice in and around my barn.

    • avatar

      Hi Mark,

      I thought I had it rough handling 80 pound bales back when I worked with elephants and hoofstock!

      In zoos we bury snakes eggs half way (1/2 mass exposed) in a covered container as described here: http://blogs.thatpetplace.com/thatreptileblog/2008/10/08/incubating-reptile-eggs-a-simple-method-of-monitoring-moisture-content/; but other techniques can work, esp at end of incubation period. I wouldn’t use damp straw…things change once you move the eggs..even if you use same substrate – straw – the environment will be radically different. Fungus grows easily on decaying plants, can spread to and kill eggs. Peat moss, sphagnum, vermiculite or even slightly moist sand would be preferable…if you use sand (or topsoil), place eggs in a slight depression but do not bury 1/2 way, as oxygen circulation will be limited; ple ase let me know if you need anything, best, Frank

  2. avatar

    Hello again.well I have one hatchling. Not gray or brown, caught a glimpse of its tail. Striped orange ish red to dark brown. Very small in diameter. Half as thick as a pencil. Not sure of its length, escaped into the straw. I found the egg it escaped from. A little foam at the top of it an a hole as big as a pencil. I picked it up and could tell it was empty by the weight. There were two like that.so two out of twelve. We are getting there. No pictures as of yet. What is a good starting diet for them? Crickets from the bait store? Frozen baby mice? Anyway, will keep you up to date with more hatchings. Have to go to work for the next twelve hours.

    • avatar

      Hi Mark,

      Nice to hear…the species you mention may be able to take small sections of pink mice, or perhaps entire pinkies. Some take small lizards as well, rarely earthworms but usually not crickets. I’ll check FB shortly, Enjoy, best, Frank

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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