Sea Turtles on Cape Cod

Rescued Kemp's ridley surrounded by dry seaweed
Kemp's ridley surrounded by dry seaweed

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When most people think of sea turtles, they imagine these marine reptiles enjoying the warm waters of the tropics. However, visitors and residents of the Cape may not realize that each summer hundreds of these turtles make their way into Cape Cod Bay!

While sea turtles don’t nest north of the Carolinas, many juvenile sea turtles spend their summers in the Bay, feeding on the plentiful crabs, jellyfish, and algae.

Sea turtles are difficult to spot, though boaters may be lucky enough to see one come up to the surface for a breath of air. If you spot a sea turtle during summer, please report it to

If You Find a Cold-Stunned Sea Turtle 

It's very important to recover these stranded turtles as quickly as possible. Do not assume a turtle is dead—turtles that appear lifeless are often still alive. Please note that it's illegal under both state and federal law to harass sea turtles or transport them without a permit.

If you come across a stranded sea turtle on the beach, please follow these simple steps:

  1. Move the turtle above the high tide line. Never grab or hold the turtle by the head or flippers.
  2. Cover it with dry seaweed or wrack.
  3. Mark it with an obvious piece of debris—buoys, driftwood, or branches.
  4. Call the Wellfleet Bay hotline at 508-349-2615 x6104.

About Cold-Stunned Sea Turtles

Mass Audubon staff member examining a sea turtle © Esther Horvath
Mass Audubon staff member examining a sea turtle © Esther Horvath

Excepting the Leatherback, sea turtles are ectothermic—their body temperature is regulated by the temperature of the water around them. As winter approaches, the water temperatures in Cape Cod Bay slowly decrease and sea turtles begin to make their way south to warmer, tropical waters.

What Does "Cold-Stunned" Mean?

Every year since the late 1970s, some number of juvenile turtles don't make the journey out of the Bay in time to head south. Trapped by the "hook" of the Cape, they become disoriented in the currents. When the water reaches about 50°F by mid-November, these disoriented turtles become too cold to eat, drink, or swim—they become cold-stunned.

Unable to move, these turtles are at the mercy of the winds and currents. When strong winds blow in from the north or west, cold-stunned turtles can be pushed up onto the beach by the high tide and left behind as the water recedes during low tide.

What We Do

Luckily, all is not lost for these sea turtles! Since 1979, Wellfleet Bay staff and a corps of over 250 volunteers have patrolled the beaches of Cape Cod night and day during high tide, on the lookout for cold-stunned turtles. Any turtle they find is rapidly transported to the sanctuary and then on to the New England Aquarium for evaluation and rehabilitation.

How You Can Help

If you are interested in volunteering with our sea turtle stranding rescue, please call us at 508-349-2615. 

In addition, this yearly rescue effort wouldn't be possible without both monetary and in-kind donations from our supporters. We hope you'll consider making a donation online—gifts of any size are welcome and very much appreciated! To donate supplies, please call 508-349-2615 or email us

Summer Sightings

For boaters, if you see a sea turtle during the summer please report it to

Sea Turtles of Cape Cod

While unlikely, it is possible to find five species of sea turtles on the Cape. 

All of following species are listed as either "Threatened" or "Endangered" under both the Massachusetts Endangered Species Act (MESA) and the U.S. Endangered Species Act (ESA). This means it's illegal to harass them, and you cannot transport them without a permit.

Kemp's Ridley (Lepidochelys kempii)

STATUS: Endangered
At once the smallest and most endangered sea turtle in the world. Ironically, the Kemp's Ridley also the most common turtle found cold-stunned on Massachusetts bayside beaches. Juveniles are typically only 5-10 pounds, but adults can grow up to 100 pounds. Several hundred typically strand each winter on Cape Cod. Learn more >

Loggerhead (Caretta caretta)

STATUS: Threatened
This species has the largest geographic distribution of any sea turtle in the world. Juveniles can vary widely in size—between 30-200 pounds—and full-grown adults can exceed 400 pounds. Loggerheads are becoming a commonly stranded species on Cape Cod. In recent years, an average of 24-26 are found cold-stunned, with a high of nearly 150 in 2012. Learn more >

Green (Chelonia mydas)

STATUS: Threatened
Named for the green color of its body fat, Green Turtles are growing increasingly threatened. Like the Loggerhead, this species has begun stranding on Cape Cod beaches in increasing numbers during the winter months—up to a few dozen per year in the past few years. Juveniles can weigh anywhere from 5-25 pounds, and adults can reach an impressive 400 pounds. Learn more >

Leatherback (Dermochelys coriacea)

STATUS: Endangered
These are the largest turtle species—and the heaviest reptile—in the world. Leatherbacks are also the only sea turtle that can regulate their body temperature internally, unlike most reptiles that rely on their external environment for warmth. Thanks to this adaptation, Leatherbacks don't cold-stun. But they can still be severely injured or killed by boat strikes, fishing gear entanglement, and ingesting plastic. Full-grown adult Leatherbacks can reach up to eight feet in length and weigh 1,500 pounds! Learn more >

Atlantic Hawksbill (Eretmochelys imbricata)

STATUS: Endangered
This species rarely leaves tropical water, making it the least common sea turtle found near Cape Cod. Only one or two cold-stunned individuals have ever been recorded. The Hawksbill is listed as "Endangered" under both the MESA and the federal ESA. Adults can reach up to 180 pounds. Learn more >


Kemp's Ridley, Loggerheads, Greens, and Hawksbills will all hybridize with each other on occasion, and several hybrids have been found cold-stunned. Careful scrutiny of scute pattern is required to identify a hybrid as such, and genetic testing is necessary to determine the parent species with certainty.