That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

Recently I reported on a study that documented declines of 50-90% in 17 populations of 8 snake species (please see article linked below).  These findings brought to mind the global amphibian decline that was first uncovered in 1990.  Since then, an emerging disease caused by the fungus Batrachochytrium dendrobatitis has likely caused the extinctions of over 100 frog species.  Researchers seeking to avoid a similar crisis among the world’s snakes have now identified an emerging illness, Snake Fungal Disease, as cause for serious concern.  Associated with a newly-described fungus, Chrysosporium ophiodiicola, the disease has been found in several species in 9 states (USA), but is likely much more widespread.

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New Victims of a New Fungus

The global snake declines mentioned above first came to light in the late 1990’s, but explanations remain elusive.  In 2008, herpetologists became alarmed when Eastern Massasaugas (or Swamp Rattlesnakes) in Illinois and Timber Rattlesnakes in New Hampshire showed evidence of an unusual fungal infection.  A fungus (Chrysosporium sp.) that had previously been isolated from captive snakes, but never in the wild, was identified from head lesions on the Timber and Swamp Rattlesnakes.  All of the snakes submitted for study expired.

In April of 2013, the USGS National Wildlife Health Center announced the discovery of a fungus new to science, Chrysosporium ophiodiicola.  This fungus has been implicated in an emerging disease that is now afflicting snakes in the Eastern and Midwestern USA.  Increasing numbers of snakes showing evidence of infection have been found by USGS biologists, who fear that the disease may devastate snake populations. Read More »

In recent years, researchers have found toxins in a wide array of snakes and lizards formerly believed to be harmless…even the Bearded Dragon is not above suspicion (please see below), but venomous pythons?  While working at the Bronx Zoo, I was several times called upon to assist in confiscating snakes that had appeared in the pet trade before we learned of their potentially lethal venom (i.e. Asian Watersnakes, genus Rhabdophis). All evidence of toxicity must be taken seriously…bear in mind that both the Boomslang and Savanna Twig Snake were thought to be harmless until each killed a prominent herpetologist!  The recent discovery of toxins in the mucus of certain pythons poses a unique and unexpected concern for snakebite victims.

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Python Venom

Studies at the University of Queensland have revealed the presence of toxins in the mucus of several python species.  Described as “relic venom”, they occur in only trace amounts. In common with many other snakes, pythons may have relied upon venom at some point in their evolutionary history.  Although they no longer utilize venom to overcome prey or defend themselves, pythons continue to produce some toxic compounds.  While some snakes bear toxins that target specific animals (i.e. Tentacled Snakes, Erpeton tentaculatum, which prey upon fish), python toxins seem to have no use, and pose no danger to people.

The toxin molecules thus far identified in pythons differ from those found in any known venomous snake.  Being so chemically unique, they are of great interest to those seeking to develop new chemical compounds and medicines. Read More »

As any experienced reptile enthusiast knows, accounts concerning the size and aggressive nature of various snakes are usually highly exaggerated. The Black Mamba, however, comes close to living up to the legends that surround it, and has long been among the most feared of all African snakes. In the course of a lifetime spent working with venomous snakes in the wild and captivity, I’ve come to regard it as deserving of a special degree of respect. Today we’ll take a look at its natural history and behavior.

Description

The Black Mamba is the longest of Africa’s many venomous snakes. It is slender in build and averages 8-9 feet in length, but 14 footers have been recorded. Also very agile and fast-moving, several individuals have been clocked at 12.5 miles per hour. Black Mambas often travel about with the head held high, in a manner similar to that of North America’s Black Racer.

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The “black” part of its common name is derived from the color of mouth’s interior, which is displayed when the animal is threatened (North America’s Cottonmouth behaves in a similar fashion). The body color may be various shades of brown, olive or gray, but is never black.

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As a small boy, I devoured the books of Messrs.’ Ditmars, Kauffeld, Whittaker, Sanderson and others who sought out snakes in their natural habitats. The formidable Black Mamba, (Dendroaspis polylepis), accorded respect by all, was given a special place of honor by legendary snake man C.J.P. Ionides in Mambas and Maneaters. Although I was eager to expand my snake hunting experiences, these authors convinced me that this longest of Africa’s venomous snakes was better observed than handled. Fate intervened, however, and I wound up working closely with what has been described as “Africa’s deadliest snake”. Accounts of the recent escape of a Black Mamba from the Pretoria Zoo brought an experience of my own back to mind…

Uploaded to Wikipedia Commons by Tad Arensmeier

Handling Mambas and Cobras

Zoo-based reptile keepers such as I handle thousands of venomous snakes over the course of their careers. A snake hook generally fits the bill for routine tasks. The Black Mamba, King Cobra and several related species, however, present special challenges, especially when they reach full size. Quick, high-strung, and seemingly more alert and intelligent than others, many Elapids (cobras, mambas and their relatives) are difficult to move via snake hooks….all old reptile keepers have their stories. You can read about my adventures with an escaped King Cobra in this article.

I was fortunate in having had the benefit of working with several older, well- experienced keepers, and had no illusions about “proving” myself when it came to cobras and mambas. I feel that “discretion is the better part of valor” where they are concerned, a belief confirmed by observations made in the course of responding to many snakebite emergencies over the years. Whenever possible, I relied upon shift cages or other “tricks” (please see article below) when I needed to move a mamba.

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Many interesting reptile field research reports are published in professional journals that are not available online to non-subscribers. Fortunately, I’ve long had access to many of my favorites, including Copeia, Herpetologica, and Herpetological Review.  From time to time I like to provide summaries of interesting reports that I have read and enjoyed.  Today’s article covers some very unique snake feeding observations drawn from recent publications and my own experiences in the field and among zoo animals.  Please be sure to post your own observations below, thanks.

When Prey Exceeds Predator’s Mass

The largest snake meal that I’ve personally witnessed was a 60 pound White-Tailed Deer taken by a 17 foot-long, 215 pound Green Anaconda, Eunectes murinus, in Venezuela. A 130 pound Impala consumed by an African Rock Python, Python sebae, is the largest fairly reliable meal I’ve been able to document (please see article linked below).

But in terms of the ratio of prey size to snake size, a Red Duiker (small antelope) eaten by a Gaboon Viper, Bitis gabonica, beats most accounts hands down.  The antelope outweighed the snake by 4%!  In addition to being the largest meal recorded for this species, this is also the first record of an ungulate being taken by a Gaboon Viper in South Africa.  I’ve worked with Gaboon Vipers in zoos, and know how well-adapted they are for taking large, infrequent meals, but I was still quite surprised by this observation. Read More »