Even though I caught and kept a newt in a small terrarium for several years when I was growing up in Western Pennsylvania, I am not particularly interested in reptiles and amphibians and thus do not know much about them. Recently while hiking on a side trail between the North and South Elkins Barns at Ash Creek Wildlife Area (Lassen County CA), Leonard and I found a cavity in the ground surrounded by white, elliptical eggs. They did not resemble bird eggs, but seemed to be the shape of turtle eggs. One Pacific Coast, native, fresh water turtle common in our area is the western pond turtle, a denizen of streams, ponds, marshes and rivers. It basks in shallows and along emergent logs, vegetation, rocks or other “platforms”, escaping to safety by quickly splashing into the water when disturbed. These eggs were on hard ground far from water. Time to check out the books!
I was surprised to discover that western pond turtles lay their eggs up to 1/2 mile from the nearest source of water. In late spring or summer, the gravid female heads onto dry land during the late afternoon or early evening in search of a nesting site. Once a suitable location is chosen, the female urinates on the hard ground to loosen the soil. She then scrapes and digs a pear-shaped cavity in the earth with her hind legs. If a rock or other obstruction hinders her digging, she will abandon the site and search for another.
Once the nest chamber is completed the female lays between 3 and 15 eggs. The eggs have hard shells similar to those of birds rather than the leathery eggs of other turtle species. Once the eggs are laid, the female back-fills the cavity with dirt, grass and leaves, making the site undetectable. Her maternal duties are now complete.
The incubation period is about 3 months. Most of the hatchlings overwinter in the nest chamber, emerging the following spring, however, some hatchlings in warmer areas will leave the nest in the fall. The sex of western pond turtles is determined by incubation temperature with males developing under 86° F and females above that temperature. Independent at birth, the vulnerable little turtles immediately search out the safety of the nearest water.
Western pond turtles have disappeared from their Canadian range and are rapidly declining in Washington and Oregon. Many programs involving zoos and other groups are in place to breed and raise these long-lived reptiles (up to 50 years) in captivity before reintroducing them to their native habitats in an effort to save the species.
The classification of the western pond turtle is in flux. Originally designated as Clemmys marmorata, the currently accepted scientific name is Actinemys marmorata. (To further confuse the situation, some separate A marmorata into two separate species – a northwest pond turtle and a southwest pond turtle.) Emys marmorata is another synonym for the western pond turtle. Although I used Clemmys marmorata in a previous post about western pond turtles (see “Western Pond Turtle” 05-07-2012), I believe Actinemys marmorata is currently more correct. Pacific pond turtle is another common name for this reptile.