Thursday, June 10, 2010

Shell Game

Although it was too shy to come out of its shell and pose for a portrait, I handled this small turtle with care as it has a nasty disposition completely out of proportion to its size and won't hesitate to bite. Common Musk Turtles (Sternotherus odoratus) are often called "Stinkpots" for the rank musk they secrete. Note the high domed carapace, the stripes on the side of the head and the barbels on the chin.

Note the reduced plastron, very similar to that of a Snapping Turtle.

The turtle was wandering around in the gravel at the boat ramp, not a good place to be as people backing in with a loaded trailer aren't apt to notice an animal this small. I moved the turtle to the edge of the lake; the following three images show it slowly and suspiciously peeking out to make certain it's safe ... and finally dashing for the safety of the water.

Despite its youth this tiny Snapping Turtle (Chelydra serpentina) was quite fearless. A Snapping Turtle's shell is of no use as a retreat if danger threatens. The large adults are competent at defending themselves but at this age the turtle is helpless. Most hatchlings fall prey to gulls, fish and other predators long before they have a chance to mature.

Shortly after the encounter with the Musk Turtle I had to perform another rescue, this time a Painted Turtle (Chrysemys picta) wandering along the Eastern Ontario Trail.

This turtle has a freeloader leeching a ride and meal.

A couple of closeups of the little sucker ...

Leaving the shell of its nymphal exoskeleton behind for the last time, a teneral damselfly is waiting for its wings and body to harden and become rigid enough to make its maiden flight to the relative safety of some nearby shrubs. I don't know what species this might be, based on its size and shape I'm going to guess at a female bluet.

The little jewel on the bindweed leaf is a Mottled Tortoise Beetle (Deloyala guttata). The thin extended outer edges of the elytra and pronotum forming the "shell" are transparent. Bindweed and other members of the morning glory family are the beetle's favoured food plants. I don't have any photos as yet but another common local species is the Golden Tortoise Beetle (Charidotella sexpunctata), which at a quick glance can be mistaken for a ladybird beetle.

Two of the common local species of land snail are out grazing after a rain. Generally molluscs such as clams, squids, and in fact most snails, are found in a watery habitat. Like all molluscs, these land snail's soft moist bodies would dehydrate quickly in the relatively hostile environment of the forest floor. Part of the shell's purpose is to keep moisture in, which leads one to wonder ...

... about slugs. Slugs still have a rudimentary shell; it's visible just behind the eyestalks. But it's buried under the slug's moist outer skin and seems to be of no obvious use for protection from either predation or the elements. Similar animals, similar environments, similar lifestyles. Yet the ultimate games of natural selection and survival worked in favour of some species keeping their shells, and others not. Why the difference?