ORLAND – It’s turtle time in Maine.

Common snapping turtles are on the move, and their migration often takes them near and across Maine roads, providing an attraction for some drivers and a target for others.

The snappers came out of hibernation last month in Maine and have already bred in their home ponds. The otherwise sedentary animals are searching for the ideal spot to lay their eggs and are much more visible than at any other time of the year.

They can cover miles in search of the right spot, stopping to rest and eat in vernal pools along the way.

But often they’ll settle along the roadside. As it happens, human activity has created the right nesting conditions in the gravel shoulders along Route 1 and other roads throughout the state. The soft shoulders provide the snappers with an area in which they can dig nests to hold their annual clutch of eggs.

They may also be attracted to the heat emanating from the asphalt roadway, according to researcher Susanne Kynast, who is studying the reptile in Washington County.

Temperature is a factor in the laying process, Kynast said.

As they search for a potential nesting site, the females seek an area that is the right temperature. They need a spot that is 84 degrees F. in order to ensure a 50-50 split of male-female offspring. A little colder or warmer, and there will be more males or females, she said.

Often, a female will dig a hole and lie in it for a while to determine if it is the right temperature, sort of a reptilian test pit. On occasions, Kynast said, she has found a nest with seven or eight test holes nearby.

But what might be the breeding grounds for new generations of turtledom, has also turned into death row for adult turtles mowed down by passing traffic.

Females snappers, which are the ones that migrate in search of nests, suffer the most and have high mortality as road kill on Maine’s roads.

“The vast majority of females are killed before they’re 45 years old,” Kynast said.

Females generally start laying at age 21, she said, and although 20 years of laying may seem like a lot, the turtles suffer an extremely high mortality among the young. About 90 percent of the deaths occur in the first night after the eggs are laid, mainly due to predation by raccoons, she said.

“The chance of survival is one in 1,500,” Kynast said. “That means a female will have to lay 3,000 eggs just to replace herself and her mate.”

Although the laying rate varies based on size, at an average of 30 eggs per year, a female has to lay for 100 years just to sustain the population, she said.

In the past, which for the snapping turtle stretches back about 2.4 million years, that has not been a problem.

With no natural predators, the snapper has a life expectancy of 170 years, Kynast said, and could live as long as 200 or 300 years. There is also evidence that females can lay high-quality eggs until they die.

But in the past 50 years, as more roads have appeared and traffic has moved faster, the deaths of adult turtles in Maine also have increased at a rate that could threaten the sustainability of the snappers. And while many of those deaths are unavoidable, Kynast said, some motorists don’t try to avoid the turtles on the road.

“They either don’t look or they don’t care,” she said.

Some people just like to hear them crunch, Kynast said. She recalled that one trucker working near a pond once bragged that he had managed to run over 50 turtles. There are no turtles left in that area, she said.

“There may be some large adult males,” she said. “But that area is reproductively dead.”

Snapping turtles get their name from their main form of defense. They face a perceived threat and will hiss and snap their sharp beak in the air. While that has been interpreted as aggressive behavior, the snappers react that way because they are vulnerable on land, according to Aram Calhoun, a professor of plant, soil and environmental sciences at the University of Maine.

The snapper has a lot of exposed flesh, particularly underneath where the shell is smaller than most other turtles, Calhoun said, and is unable to pull itself completely into its shell. In the water, where it is at home, it will generally swim away from danger.

On land, even when threatened, snappers often will bump potential threats with a closed beak rather than trying to bite them, Kynast added.

Humans can help the snappers that they find along side the road. If they are uninjured, determine which way they were headed and move them across the road in that direction. They can be picked up from behind near their back legs. There is a ridge underneath the shell there where it can be held with the head pointing away from you. Don’t lift the turtle higher than six inches above the ground, just in case it drops. If possible move it to the nearest body of water.

Turtles can survive severe injuries, according to Kynast, and can be rehabilitated and returned to the wild, although the process can be long and relatively expensive.

Anyone finding an injured snapping turtle can contact Kynast, who is a rehabilitator, at 255-6120.