No. 12–Diamondback Terrapins, Part I

Except for brief perfunctory liaisons in the spring and occasional encounters on sunning logs, where they largely ignore each other, diamondback terrapins in the wild are solitary creatures that range widely through the lowcountry and yet are rarely seen except, sadly, as road kill.

A favorite among visitors, the two young terrapins that share habitat at the Estuarium are, on the other hand, quite gregarious and attention seeking. Visitors mean one thing to them, FOOD, and their agitation rises as humans approach. Feeding time is spectacularly chaotic with much splashing, shoving, dunking and neck stretching. If they had a vocabulary, sharing would not be in it.

Terrapins are distinguished from aquatic turtles, tortoises and box turtles in that frequent they both land and water. Aquatic turtles will haul out to sun but rarely stray far from their home body of water. The exception may come with over crowding forcing an overland search for a new home.

Tortoises like the Gopher Hill Tortoise found in the sand hills of neighboring Ridgeland and their giant cousins of the Galapagos are full time land. The same is true for the many species of box turtles, individuals of which have spent time in a box in virtually every home in America that at one time or another was occupied by children.

There are seven subspecies of diamondbacks which inhabit brackish water estuaries from Cape Cod to the Texas coast. Available literature that I have reviewed states that diamondbacks inhabit brackish water exclusively. Our local subspecies, however, is known to frequent fresh water ponds. The two Estuarium residents have a double tank set up with a fresh water and water from Battery Creek. They are almost always in the fresh water when I arrive each morning.

Unlike most estuaries, Port Royal and St. Helena sounds are very high salinity systems. This may have something to do with our terrapins spending time in fresh water. I will research the matter further and report in next month’s column.

Diamondbacks are easy to identify by their coloration of gray skin with black polka dots. The concentric rings on the upper shell (carapace) give the animal its name. Females can grow to nine inches (shell length) with males much smaller at only six. They may live up to forty years but that is rare these days as the odds are stacked against them from the beginning.

It is estimated that only 20% survive the first year as they fall prey to raccoons, mink, blue crabs, herons, wood storks, and just about anything else that can get their mouths around them. As they grow they must deal with crossing roads, gators, boat props and crab pots.

Terrapin mortality due to drowning in recreational crab pots is of particular concern because it is a problem that can be rectified. More on solving the problem and the life cycle of the terrapin in next month’s issue.