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Don Lewis, Massachusetts Audubon Society,
Fox Island Wildlife Management Area

Terrapins Face Winter’s Final Test — 8 April 2001

Full moon intensifies Wellfleet Bay’s already dramatic tidal swings.  Highs rise to nearly plus 13 feet and lows plunge to almost minus 2 feet.  While flood tides threaten coastlines, lows place our sleeping terrapins at greater risk.  Vast expanses of tidal flats and marsh creeks, which are normally protected by bay water, are drained by these astronomical tides, exposing turtles who chose hibernacula a bit too close to the boundary.  While the numbers aren’t great, we recently discovered a pattern of terrapins being dislodged during winter and early spring tidal extremes.  After being summarily unearthed from cozy slumber, these cold-stunned turtles are discovered — if they’re lucky — stumbling along the high tide line where they’ve been washed ashore.  Unless found, most will not survive prevailing air and water temperatures in February, March, and even April.  Today, in this so far bone-chilling springtime, we reached 39 degrees under cold rain and water temperatures over the tidal flats remained in the mid-40s.

As low tide approached this evening and Lieutenant Island’s marsh drained dry, a resident braved the gloom and bitter weather to discover a cold-stunned terrapin in the high tide wrack.  A 1-year-old turtle hatched in the fall of 1999, this one proved a special find, indeed.  Like most researchers, we rarely see terrapins between the time they disappear into the nursery marsh immediately after hatching and when they pop up again as strapping 3- & 4-year-old juveniles.  The lost years between birth and then are mysteries.  So, we are doubly blessed by today’s discovery.

The turtle measured 4.5 centimeters carapace length (4.0 cm plastron) and weighed in at 16 grams.  The age was confirmed by a single growth line.  Assuming birth in fall 1999 and average hatchling statistics, this little critter looks like it gained a little more than 1.5 centimeters in length and double its 8 gram birth weight in its first season of activity (Year 2000).

Since Flower, the free-loading hatchling box turtle, who moved into my garage in November, has the terrarium booked for the season, I set up a make-shift home for this new boarder.  It’s resting on moist beach sand with a small amount of marsh water at one end, which is heated by a lamp to gradually raise its body temperature.  When first examined, the eyes seemed closed and filmy, but they were still responsive to light.  I witnessed this same pattern in a 3-year-old juvenile (Vito), which was found cold-stunned in the same tidal condition in February 2000 and released last spring.  If the heat works its magic, I expect to see the eyes open in a day or two.

This young terrapin sports an interesting and anomalous carapace pattern of 19, rather than 13, scutes.