Resistance of the Opossum (Didelphis Virginiana) to Envenomation by Snakes of the Crotalidae Family.
Technical rept. Dec 74-Aug 75,
EDGEWOOD ARSENAL ABERDEEN PROVING GROUND MD
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Whether the North American opossum, Dipelphis virginiana, has a natural resistance to envenomation by 12 species of snakes from the families Crotalidae, Viperidae, Elapidae, and Hyprophidae was studied. Challenge of the anesthetized opossum was by actual snakebite or intravenous injection of 4 to 20 times the dose known to be lethal to susceptible mammals. Some animals that survived the snakebite were given venom intravenously 40 to 90 minutes after the bite. Heart and respiratory rate, EKG, and blood pressure were monitored for 2 hours after envenomation, and surviving animals were observed for signs of poisoning for 30 days. The opossum survived the venom of the following snakes of the Crotalidae family eastern diamondback rattlesnake, western diamondback rattlesnake, copperhead, cottonmouth moccasin, Mexican copperhead, and Central American mossasin. It died when challenged with the venom of the Indian cobra, Chinese cobra, coral snake, cape cobra, puff adder, and sea snake.