Turtles

Eastern Snapping Turtle skull displaying the keratinized sheaths which line the beak.

National Park Service

Turtles are a type of reptile with their defining characteristic being a shell made from fused ribs and vertebrae. They are one of the oldest living reptile groups and first evolved around 220 million years ago. Since then, turtles have come to inhabit a wide variety of habitats from marine to freshwater, and are found on every continent except Antarctica. Although turtles are a diverse and varied group of vertebrates, they all share some characteristics. All turtles have a shell and lay eggs on land. Turtles do not have teeth, but rather beaks lined with keratinized sheaths, which are modified scales that cover the beak.

A turtle's shell is a unique feature among vertebrates and helps protect them from predators. Different species have shells that vary in color, shape, and pattern, so it can be a helpful tool for species identification. It is composed of two separate pieces: the carapace and plastron. These pieces fuse together on the side of the shell in an area called the bridge. The carapace is the upper shell. It is covered with keratinized scutes, which are large epidermal scales or plates made of the same material as fingernails and hair. Softshell turtles lack keratinized scutes. Instead, leathery tissue covers the shell. The plastron is the lower shell.

 

Eastern Snapping Turtle

National Park Service

Turtles typically nest during the summer months. Female turtles lay eggs, cover them with substrate, and then abandon the nest. Some turtles exhibit temperature-dependent sex determination, meaning that the egg's temperature during a certain period of development determines the sex. For example, in Eastern Snapping Turtles, females develop at high and low incubation temperatures while males develop at intermediate temperatures. After about two to three months of incubation, the hatchlings emerge from the nest. Sometimes, hatchlings remain in the nest and overwinter there, waiting to emerge until spring. Nests and hatchlings are highly vulnerable to predation by skunks, raccoons, foxes, and other predators.

 

Painted Turtle

Scott Rando

Within the Upper Delaware Region, turtles are found in streams, rivers, marshes, bogs, and ponds. Turtles are usually most active from spring to fall, spending the wintertime in a form of hibernation called brumation. Some turtles like the Painted Turtle are diurnal, meaning they are active during the daytime. Others like the Eastern Snapping Turtle tend to be active during either the daytime or nighttime. Visitors can often see turtles basking in the sunlight on logs or rocks. Basking is an essential behavior for turtles. By spending time in the sunlight, turtles can completely dry off, preventing fungal and bacterial infection. In addition, basking helps turtles regulate their internal body temperature and ensures they obtain the appropriate amount of UV rays. Without absorbing adequate UV rays, turtles wouldn’t be able to produce vitamin D3, which allows them to process calcium.

Turtles have a varied diet but are generally omnivorous, meaning they consume both plant and animal material. For example, Wood Turtles typically consume worms, slugs, snails, fish, tadpoles, leaves, algae, moss, berries, and mushrooms.

 

Wood Turtle

National Park Service

Threats to turtles today include habitat loss, road mortality, poaching, water pollution, and more. The Wood Turtle, found in the Upper Delaware Region, is listed as endangered by the International Union for Conservation of Nature, and is considered a species of special concern in both New York and Pennsylvania. Be cautious driving along roadways located near streams that may house Wood Turtle populations. Wood Turtles may try to cross roadways when traveling to and from nesting and foraging areas.

The Eastern Snapping Turtle, Wood Turtle, and Painted Turtle are native to the Upper Delaware Region. Painted Turtles found in the area may belong to the Eastern or Midland subspecies, though some individuals exhibit characteristics of both subspecies.

Pond Sliders are a nonnative turtle species sometimes found in the Upper Delaware Region. In particular, the Red-eared Slider subspecies, is a popular pet that is often illegally released into water bodies when owners become tired of them. Due to these releases, Pond Sliders are found all over the United States and the world, and compete with native turtles.

 

Turtles found in the Upper Delaware Region include:

Eastern Musk Tutle (Sternotherus odoratus)
Eastern Painted Turtle (Chrysemys picta picta)
Eastern Spiny Softshell Turtle (Apalone spinifera)
Midland Painted Turtle (Chrysemys picta marginata)
Northern Map Turtle (Graptemys geographica)
Pond Slider (Trachemys scripta)
Eastern Snapping Turtle (Chelydra serpentina)
Wood Turtle (Glyptemys insculpta)