Duvernoy's Gland Secretions in Colubrid Snakes

The Colubridae family of snakes includes 320 genera and about 700 species. Until the 1920's (some authorities say the 1950's) these snakes were considered utterly non-venomous. Not harmless, just non-venomous, as the word "harmless" cannot accurately describe a family, wherein certain members bite with teeth that pierce the skin and splatter blood. The wound often heals quickly, precisely because profuse bleeding cleans the punctures, and for true herpetologists that makes an occasional bite from a "non-venomous" snake an acceptable part of herping, not to mention a badge of distinction. Herping, one might say, isn't for sissies.

Many colubrids, however, are anything but non-venomous. O'Donnel et al mention, with particular reference to ring-necked snakes in the genus Diadophis, that despite an absence of specialized venom delivery systems like those of vipers and elapids, many colubrids have advanced salivary glands (Duvernoy's) that produce proteins with phospholipase A₂ activity. These scientists then note that phospholipase A₂ is a common component of elapid and viperid venom.

When serpents with phospholipase A₂ activity bite their prey the mechanical effects of the bite are synergized by the chemical effects of their saliva. For many if not most of these snakes, the phospholipase A₂ activity in their salivary secretions isn't merely sufficient to anesthetize, but to actually kill that prey.  Michael Smith, in his humorous paper on Duvernoy's glands and what he calls "warm" herping (as distinguished from "hot" herping, i.e., the keeping of highly venomous serpents), discusses this topic as it pertains to hog-nosed snakes in the genus Heterodon, and garters in the genus Thamnophis. For Smith, who writes tongue-in-cheek, discovering that his beloved garter snakes were mildly venomous was a true esteem-raising experience. The question is, how dangerous is this venom to man?  NEXT PAGE ---- Page Menu:  1  *  2  *  3  *

* TERMITE ENCOUNTERS  *  SNAKE ENCOUNTERS * SNAKE BITE FIRST AID * SNAKE EXCLUSION * SPIDER ENCOUNTERS FOR 2008 *  SPIDER ENCOUNTERS FOR 2007 * SPIDER BITE FIRST AID * SPIDER EXTERMINATION * PUSS CATERPILLAR ENCOUNTERS * PUSS CATERPILLAR FIRST AID * PUSS CATERPILLAR EXTERMINATION *  Assembled & Edited by Jerry Cates. Questions? Corrections? Comments? BUG ME RIGHT NOW! ---- Ph: 512-331-1111 ---- E-Mail ---- Privacy ----BugsInTheNews * --0a0s--