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. Eggs at the top of the nest are often significantly warmer than those at the bottom, resulting in all females from the top eggs, and all male from the bottom eggs. In some locations, the hatchlings emerge from the nest in hours or days, and in others, primarily in locations warmer than northern New England, they remain in the nest through the winter. When they emerge above ground, the hatchlings, without any adult guidance, make their way to the nearest body of water, which can be up to a quarter of a mile away, and once there, seek shallow water.
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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.