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There's nothing new about bears wearing radio-transmitter collars.

Nor is there anything new about such transmitters on elk or cougars or moose or even certain birds.But rattlesnakes?

"Yea, it sounds a little unusual," admits National Park Service biological technician Dave Rose. But it's also a good way to study the snakes to determine whether an unusually large rattlesnake population is compatible with large numbers of park visitors and employees.

Historically, the park service would catch the rattlesnakes - more specifically the midget faded rattlesnakes - and remove them from the park. "We didn't want to extricate them from the park if we could help it," said Rose, "and since animals in the park are protected, it was decided to find out why there are so many rattlesnakes."

In particular, the Park Service wanted to know why there is such a large concentration of rattlesnakes around the residential area where park employees live. Sixteen different rattlesnakes have been spotted in the residential area so far this year, and as many as 20 different snakes a year have visited in the past.

Were the homes built over a den of snakes? Or were they migrating in? If so, why and where from? Were they coming in for water or because of the trees and foliage? Or was human garbage attracting rodents that were easy prey for the snakes?

"In the spring when the rattlesnakes started showing up, we caught some larger ones and put radio transmitters in the snakes," explained Rose. "We surgically implant the transmitters just below the stomach and then sew them back up."

The transmitters are about an inch long and have an antennae about 6 inches long that coils through the intestines of the snakes.

Rose's job entails tracking the snakes. "I track them every day that I'm here, looking at the microhabitat, what kind of ground are they sitting on, what kind of logs and bushes they are hiding under. I look at what kind of solar radiation they getting and how they are foraging."

The study of rattlesnakes in Natural Bridges has been going on since 1983 when the then-superintendent started catching snakes, anesthetizing them and then photocopying before releasing them (each snake has a unique diamond pattern on its back that distinguishes it from all other rattlesnakes).

Rose prefers a Polaroid camera and radio transmitters in his research.

So far, transmitters have been implanted in four snakes, and indications are that the snakes don't move very far. One snake moved about a half-mile away, but most stay within 100 yards of the residence area.

When snakes are removed, most don't return. Only two snakes came back after they were removed more than 100 yards away. "They stay close, but they don't come back in," said Rose.

The study has also revealed that while some snakes come back year after year, most are newcomers. And virtually all are adults.

"Also we are finding out a lot about the life cycle of the (midget faded) rattlesnake, what kind of migration do they go through, what kind of habitat they like, and what time of the year they mate, which is different than other species of rattlesnakes," Rose said.

The radio transmitters have a 3-6 month life and are temperature sensitive. The transmitter's signal speeds up as the snake gets warmer, allowing researchers to determine the temperature of the snake by the beat that it's putting out.

The signal gets really slow in the winter. "Next month, we'll put new transmitters in them so we can track them to their den for the winter. When they come out next spring, we can track them again."

While some people may criticize the rattlesnake study as a waste of taxpayer money, Rose defends the project as an important study of man's interaction with the southern Utah ecosystem.

"By understanding them better, perhaps man can learn to live with them better. Snakes are not as dangerous as people think. They are a part of the environment, and they been here longer than man has."