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October 2005

Release date: October 12, 2005

Angelo State Professor Finds Two-Headed Rattlesnake

Though snakes have often been seen as devious and sneaky in folklore and legend,Dr. Chris McAllister may have come across the ultimate two-faced reptile - a two-headed western diamondback rattlesnake.

The Visiting Assistant Professor of Biology at Angelo State University found the young rattlesnake in September during a weekend field trip to the Head of the River Ranch in Tom Green County. Not surprisingly, he discovered the reptile lurking beneath a rock

"We had been told there were rattlesnakes on the ranch and to be careful, so we knew we might find some," McAllister said.

McAllister turned over a rock and picked up the eight-inch-long snake. At first he failed to realize what he had. Then to his surprise, a student pointed out the second head. He realized at that point he was holding one of nature's rarities.

"I thought I was lucky I didn't get bit because I had a hold of only one of the heads," McAllister said.

As far as McAllister knows, the specimen he found is the only reported instance of a two-headed western diamondback rattlesnake. Non-venomous snakes such as king and rat snakes, as well as turtles, have been found with two heads, he said, but no documented western diamondbacks.

The snake put on a show by shaking its rattle, but it was reluctant to strike at objects. This proved fatal for the snake, as it refused to eat.

Instead of letting the snake starve to death, McAllister euthanized the snake near the end of last month. He was then able to dissect the animal, which provided insight on the snake's soft anatomy.

McAllister, who spent five days in a Dallas hospital after a 1996 rattlesnake bite, said the hatchling's left head was the dominant one, but each head had its own primary nervous system, evidenced by the fully formed features- such as eyes - on both heads and the fact that both stuck their tongues out independently. He also found that the snake had two hearts, two gallbladders and a divided liver.

The rare find occurred during the annual outing of ASU's local Beta Beta Beta biological honor society to observe and collect uncommon specimens for study. The snake has been deposited in the amphibian and reptile section of the Angelo State University Natural History Collection. Its accession number is 14135.