A rare two-headed diamondback terrapin hatchling weighing about 5.2 grams was found at a protected nesting site in Wellfleet, Cape Cod, and taken to the Cape Wildlife Center. Photographs posted on Facebook reveal the hatchling's two distinct heads, a condition called bicephaly that occurs when conjoined twins do not fully separate during development. The center's veterinary team is closely monitoring the hatchling's appetite, growth and behavior. Diamondback terrapins are a threatened species in Massachusetts, making the discovery particularly noteworthy.
Rare Two-Headed Diamondback Terrapin Hatchling Found on Cape Cod — Vets Keep Close Watch
The hatchling’s two heads are the result of a rare developmental condition known as bicephaly that can occur in reptiles and other animals (Cape Wildlife Center )
A tiny, rare two-headed diamondback terrapin hatchling — weighing about 5.2 grams — was discovered Thursday at a protected nesting area in Wellfleet on Cape Cod and transported to the Cape Wildlife Center by staff from Mass Audubon’s Wellfleet Bay Wildlife Sanctuary.
The Cape Wildlife Center shared three photos on Facebook showing the hatchling from different angles, clearly revealing two distinct heads — a developmental anomaly called bicephaly.
The hatchling's two heads are the result of a rare developmental condition known as bicephaly that can occur in reptiles and other animals (Cape Wildlife Center)
What Is Bicephaly?
Bicephaly occurs when conjoined twins fail to fully separate during embryonic development. The condition is rare but is most often reported in reptiles such as turtles and snakes, according to National Geographic. Many two-headed animals face early challenges — including difficulty feeding or conflict between the two heads — but reptiles can sometimes survive longer than mammals.
The baby turtle is only the second case of bicephaly that the Cape Wildlife Center has seen in five years (Cape Wildlife Center)
"While we've encountered this unusual condition before, every case gives us another opportunity to learn more about these fascinating animals' anatomy and physiology," the Cape Wildlife Center wrote on Facebook. "Our veterinary team will be closely monitoring the little terrapin as we learn more about how their two heads and bodies work together."
This is the second bicephalic terrapin the Cape Wildlife Center has seen in five years. In 2021, a two-headed hatchling — described online as "McNugget-size" and reported to have six legs — drew widespread attention.
The turtle is reportedly behaving normally, according to New England Wildlife Center CEO Zak Mertz (Cape Wildlife Center)
Diamondback terrapins are listed as a threatened species in Massachusetts, which makes this find especially notable. New England Wildlife Center CEO Zak Mertz told CBS News that the hatchling appears to be behaving normally so far and that both sides of the animal look healthy.
The Cape Wildlife Center's veterinary team has experience with unusual wildlife cases. Recent examples include treating a screech owl found inside a Barnstable bathroom, caring for a coyote pup mistaken for a lost dog, and performing foot surgery on a goose while its mate watched nearby.
The center will continue to monitor the hatchling’s appetite, growth and behavior and share updates as the little terrapin develops.
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