Two Heads Are Better Than One: Rare, Double-Headed Turtle Hatchling Discovered on Cape Cod

When a tiny diamondback terrapin emerged from its egg on Cape Cod this summer, it had everything a turtle hatchling should have: four legs, a patterned shell and a short tail. Except instead of one head, this creature had two. The rare turtle with double noggins was discovered earlier this month at a protected nesting site by volunteers with the Mass Audubon Wellfleet Bay Wildlife Sanctuary.

On September 17, they brought the unusual reptile to the Cape Wildlife Center in Barnstable, Massachusetts, where veterinarians have been closely monitoring it ever since. The creature was born with a rare congenital condition known as bicephaly, which occurs “when an embryo goes to split—like it would for twins or something—but doesn’t separate fully,” Zak Mertz, CEO of the New England Wildlife Centers, which includes the Cape Wildlife Center, tells Popular Science’s Margherita Bassi. Veterinarians won’t be able to determine its sex until it gets a little older.

But in the meantime, the creature is behaving normally—swimming, eating and even showing off its dual disposition. Robyn Rohm, lead veterinary technician at the Cape Wildlife Center, agrees, adding that the left head was “biting the day he came in.” Bicephalic animals are rare—but not totally unheard of. This is the third two-headed diamondback terrapin to receive care at the Cape Wildlife Center in the last six years alone.

And Mass Audubon Wellfleet Bay Wildlife Sanctuary has seen five on Cape Cod since the early 2000s, reports the Cape Cod Times. Much about the turtle remains a mystery. Once it gets a little bigger, veterinarians will be able to use imaging techniques like CT scans and X-rays to “see” through its shell and learn more about its inner workings.

For now, the fate of the two-headed creature remains unclear. If veterinarians determine that it is strong and healthy enough to survive on its own, it could eventually be returned to the wild. If not, it will likely find a permanent home in captivity, per the Cape Cod Times.

In 2016, a woman living near Waco, Texas, spotted a baby snake with two heads in her backyard. She donated the two-headed Western rat snake to the Cameron Park Zoo, where it has lived ever since. Diamondback terrapins make their homes in the brackish waters of salt marshes and estuaries along the northeastern United States and Gulf Coast.