Snakes are on the make in park
Terry Halifax
Northern News Services
Yellowknife (May 07/01) - When spring is in the air, and the country's hardiest snakes emerge from caves that sheltered them through the Northern winter, their instincts lead to sexual congress.
For the red-sided garter snakes of Wood Buffalo National Park, that means slithering into a writhing love nest with about 30 like-minded reptiles.
"It's the consequence of many males trying to mate with the same female," explained Mark Bradley, a conservation biologist.
"It's hard to imagine that the female really wants that situation, but maybe that's just me." Bradley is conducting a count of the most-northerly reptiles who call Wood Buffalo National Park home and can be found in spring in the Salt River day-use area.
The study is part of the park's ecological integrity statement and will serve as a guide to conservation of the species.
The red-sided garter snakes of Wood Buffalo are at the northern edge of their distribution "and could be more prone to reflecting changes within the environment," Bradley said
The entire population of snakes returns to the karst cave at Salt River to hibernate and are susceptible to disturbance from predators and humans.
The snakes were most recently studied in 1986, and the male population was estimated at between 300 and 400. Parks Canada has since built a trail and day use area at the site and "some people think there are less snakes now," Bradley said.
To conduct the count, Bradley marks the snakes with nail polish - red for males, white for females.
"Males lend themselves to the type of study we're doing, while the females make it impossible," he said.
"As soon as the females get bred and they don't need the males anymore, they take off."
The previous study indicated most females would migrate across the road to a swampy area, where they feed on wood frogs all summer.
The current study is almost complete and Bradley said the numbers appear strong.
"It seems like the population is holding it's own," Bradley said. "We're part way through now, but our estimate is about 460 male snakes."
The snakes can survive cold northern winters because of the park's unique geological features. Ancient underground river systems cut through gypsum deposits to create a cosy winter home for the thin-skinned reptiles.
"The karst caves stay above freezing all winter, so these animals are able to stay together in a big ball and tough it out," he said.
Farther south, where food is plentiful and winters not so harsh, snakes reproduce every year. Bradley said that to conserve energy, Northern snakes only breed every two years.
The impact of humans on the population may have a greater effect on the population than less frequent breeding, Bradley suggests.
"We found 36 dead snakes and only a couple due to ravens," he said.
"Three or four had their heads crushed, which look a lot like somebody's foot.The rest are all either bite wounds or puncture wounds of some kind."
Bradley says the wounds were likely caused by dogs brought to the area and allowed to run off-leash.
"It's hard to imagine that a natural predator would go around killing snakes and not eating them," he said. "Dogs can cause a lot of damage."
He said that visitors to the park should watch where they step, stay on the trails, and keep their dogs on leash.
