The Kawartha Turtle Trauma Centre would like to pay homage this month to the Snapping Turtle (Chelydra serpentina). In 2008, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) upgraded the Snapping Turtle to a species of ‘special concern’.
This decision reflects current estimates of the Snappers range and abundance, in addition to its life history characteristics. For example, Snappers are long lived (it is thought Snappers could live to be 150!). Also, most female Snappers do not reach sexual maturity until at least 11 years old, and this is often an under-estimate. Their longevity and late age of maturity suggests that this species is very vulnerable to disturbance. So COSEWIC’s decision to upgrade the status of this historical Canadian species is an important proactive step.
So what makes a turtle a Snapping turtle? Aside from being one of the most prehistoric looking animals in our Ontario landscape, they are also our largest reptile. Brownish in colour, they can reach over 50 pounds and 36 cm long. Their carapace (top shell) is serrated giving a dangerously pointy appearance reminiscent of dinosaurs! They have long claws on sturdy legs, and a jaw that can pack a powerful bite. Snapping turtles, unlike most turtles, have a reduced shell and cannot protect themselves by pulling their head and legs into their shell. They have no natural predators in the water, but on land must protect themselves from predators the only way they can – by snapping. It is best to admire a Snapping turtle from a good distance.
Snappers prefer to live in swamps, weedy lakes, and backwater river areas, with lots of vegetation and a thick muddy bottom. Snapping turtles are both scavengers and predators, playing a significant ecological role by consuming detritus (decaying material), aquatic plants, fishes, tadpoles and frogs. Watch for them basking near the surface of bogs and swamps in early spring. The Snappers bask (lay for long periods in the sun) in order to warm themselves when they are cold. Turtles are ectotherms, meaning that they do not regulate the temperature of their bodies and so basking keeps them warm. In the winter, Snapping turtles avoid the cold by hibernating in the mud bottom of their swamp or river. They dig into the mud in early October and remain there until the following Spring (see Winter Slumber by Laurie Kryshka below for more details).
Breeding in Snapping turtles takes place in early spring (May) and occasionally throughout the summer. Females migrate to their preferred nesting grounds in early June and deposit 25-40 eggs in a nest. Nesting sites are typically found within 100 m of the shore in loose gravel-sand substrates, on gentle slopes. These well-drained substrates allow water and oxygen to move through the nest, helping the eggs develop. These sites are usually near roadways. A female that grew for at least 11 years before mating and laying eggs may be killed on the road the first time she looks for a nesting location. One study (Haxton et al. 2005) showed an annual road mortality rate of 30.5% for Snapping turtles, of which 24% were females.
Even if a female reaches a nesting site and lays eggs, between 20 and 100% of these nests can be dug up and the eggs eaten by raccoons and skunks. Many hatchlings are also eaten after hatching on their way to the water, or are picked off by predators in the water while they are still small. The sex of a baby snapping turtle is not genetically predetermined as in humans; turtle’s sex is temperature depen ent. The temperature of the nest influences how the eggs develop; at high and low temperatures female baby snapping turtles develop, while in moderate temperatures, males develop. Climate change threatens to alter the sex ratio of many organism that rely on temperature dependent sex determination, including turtles. Too few males or
females is not good for any population, especially long lived and slow responding species like the Snapping turtle.
Other threats include urban expansion and habitat loss; for example, when a wetland is filled in for housing developments. The Snappers diet has also given them a bad reputation. On rare occasions Snappers will eat small ducklings, goslings, and cygnets from the water surface when there is no other food available. For these reasons Snappers can be misunderstood and mistreated or killed by some misinformed people. The Snapping Turtle is also listed as a game species in Ontario. A valid Ontario Sport or Conservation fishing license allows a person to take up to two Snappers a day in season and possess a limit of five.
Given the immense challenges facing Snapping turtles, as well as Ontario’s other turtles, we welcome the designation of Snapping turtles as a species of special concern by COSEWIC. By promoting awareness of this species, reducing unnecessary road mortality and increasing public perception of this relict species we can prevent the Snapping turtle from further population declines and conserve the species.