Tuesday, July 14, 2009

Painted Turtles

paied turtle (c) John AshleyPainted turtles are one of the quietest members of our neighborhood. Abbey (our primary dog) will stand for an hour or more, belly-deep in the lake, watching the turtles as they silently sun on a favorite log. Jodie (our auxiliary dog) loves to carry the empty shells around whenever she finds one along shore, but she's afraid of the live ones that move.

Painted turtles live in the slow waters across most of Montana. They prefer ponds and lakes with muddy bottoms and lots of aquatic plants, but they are cold-adapted and will sometimes show up in streams and rivers. They spend the winter underwater, often submerged in the mud. In the spring they'll quietly emerge to sun on partially submerged logs. They'll start eating again in early summer when temperatures warm back up. They'll eat pretty much anything they can catch, and individual turtles that eat mostly animal matter (worms, insects, small fish) will grow faster and bigger than the ones that eat mostly plants.

Painted turtles mature slowly. Springtime courtship begins with mature males (3+ years) facing off with mature females (6+ years). His front claws are twice as long as hers, and he uses them to slowly stroke her head. If she is sufficiently impressed, then 6-20 eggs will be laid and buried in a sandy nest that is often located on a sunny bank. Nests can be hundreds of yards from water.

Adult painted turtle resting on log (c) John AshleyWhile the sun incubates the turtle eggs for 2-3 months, the soil temperature in the nest determines the sex of the hatchlings. Warmer soils produce females, cooler soils make for males, and temperatures in between will result in a mixture. After hatching, most of the baby turtles will stay buried in the nest until the following spring. They'll emerge as inch-long speed demons, seeking out the nearest water. The youngsters tend to stay in the warmer, shallower areas for the first couple of years, and their shells ("carapace") will grow about one inch per year until mature.

Turtles do not migrate, but sometimes they will travel considerable distances to seek out a different pond or lake (which is critical to maintaining genetic diversity). Highway mortality -- along with water pollution and pet trade -- can lead to significant juvenile mortality. Whenever you see a turtle on or along the road, give her an assist. Whichever direction she's facing when you first spot her, carry her off in that direction across the road and well beyond. You'll be doing your part to keep your neighborhood wild and free.