When a turtle moves its head, its eye moves to compensate, so that its eye remains in the same position – parallel to the horizon or pond surface — no matter what position the turtle’s head is in. This type of eye stabilization is called vestibulo-ocular reflex (VOR). Humans have a very similar reflex, but it’s easier to detect on a Painted Turtle (pictured) because of its dark eye line. A turtle’s eye structure is stabilized to the horizon, which makes sense, as turtles spend their life close to the ground and/or the pond surface, and this reflex enables it to align its vision horizontally in order to find food, a mate and predators.
In May, at the very same time that adult painted turtles are laying their eggs, some of last year’s young turtles are migrating from their nest site to ponds or rivers. Painted turtle eggs actually hatch in late summer, with the young turtles remaining inside the nest cavity for varying amounts of time. Here in New England, in the northern part of their range, they often overwinter in their nest and emerge the following spring.
Hibernation has come to an end for painted turtles in central Vermont, or at least for the early risers. Painted turtles actually became active a while ago, beneath the ice before ponds were completely thawed. Once some of the ice melts, they are quick to climb up and bask in the sun on any available floating log or rock, or even on the melting edge of the ice. Having spent the winter in the mud at the bottom of the pond at the rather brisk temperature of 39 degrees F. (at 39 degrees F. water achieves its greatest density and sinks to the bottom of ponds, which is where the turtles are), painted turtles are more than ready to get warm. Like black bears, painted turtles find March and April the most challenging months of the year. More of them die now than at any other time, due primarily to a shortage of food.
Every fall, roughly 3 months after they’re laid, snapping turtle eggs hatch. The hatchlings’ gender is determined by the temperature at which they were incubated during the summer. In some locations, they emerge from the nest in hours or days, and in others they remain in the nest through the winter. When they emerge above ground, the hatchlings often do so within a few hours of each other. Somehow (questions remain as to exactly how) they navigate to the nearest body of water, which can be up to a quarter of a mile away, and once there, seek shallow water . Look for young hatchlings in small brooks near ponds that are known to have adult snappers. (White object is part of the egg shell that surfaced with this hatchling.)
It’s pretty difficult to determine the sex of a Painted Turtle unless you’re extremely close to it, and they are so wary when basking that it takes some maneuvering to get a bird’s eye view of one. If you should be so lucky as to approach a Painted Turtle without having it slip into the water long before you get near it, take a look at the nails, or claws, on its front feet. Males have long claws, female short. The male uses his long claws to stroke the female’s head and neck during courtship, as well as to hold on to the female’s shell when they mate. When trying to determine the gender of a Painted Turtle, it helps when you find the two sexes together, as you can easily compare the relative length of their claws. In the photograph, the male Painted Turtle is on the left, female on the right.
A hole 4” – 5” deep surrounded by scattered empty, dried up eggshells is a telltale sign of turtle nest predation. A painted turtle (judging from the size, depth and location of the nest) dug a hole in the bank of a beaver pond last summer and proceeded to lay roughly a dozen or more eggs in it. After covering the eggs with soil, the turtle returned to her pond. The eggs hatched in August or September. Sometimes young turtles immediately climb up through the earth and emerge above ground, but occasionally, this far north, they overwinter in their underground nest and emerge in the spring. A raccoon, fox or skunk discovered this painted turtle nest early this spring (the digging was fresh) and one can only hope that by the time the nest was raided, the young had already exited and headed for the nearby pond. Research has found that a very small percentage of turtle nests avoid detection by a predator.
After spending several months hibernating in the mud at the bottom of ponds, painted turtles are out, basking in the sun. Because they are ectothermic, or cold-blooded, they are the same temperature as the air around them. In order to warm up and also to properly digest their food, painted turtles bask in the sun, and there is great competition for safe basking locations, such as rocks and floating logs. When these ideal basking sites are limited, the turtles will pile up one on top of the other, staying that way until the bottom turtle gets good and tired of supporting the turtles on top of it, and wobbles enough to make the turtle tower tumble.
It’s that time of year again
– when female snapping turtles leave their ponds and seek sandy soil in which
to dig a hole and bury their eggs. Usually
20 or 30 ping pong ball–size eggs are laid, but there can be as many as
80. The sex of the turtles that hatch
from these eggs is determined by the temperature of the eggs during their
two-to three-month incubation. Because
they are not all at the same level in the ground, the eggs incubate at
different temperatures, assuring that each batch of eggs produces both male and