# Two-headed diamondback terrapin discovery on Cape Cod

> Live situation record from CLSTR: https://clstr.news/situations/two-headed-diamondback-terrapin-discovery-on-cape-cod
> Updated: 2026-09-30T10:05:16.000Z. Sources: 7. Developments: 3.

A rare two-headed diamondback terrapin hatchling was discovered at a protected nesting site in Wellfleet, Massachusetts, on Cape Cod. The specimen, a Malaclemys terrapin, was found by Mass Audubon workers at the Wellfleet Bay Wildlife Sanctuary and transferred to the Cape Cod Wildlife Center in Barnstable on September 17.

The condition, bicephaly, is an embryonic anomaly where head structures are duplicated due to incomplete separation during early development. The hatchling, weighing approximately 4.89 grams upon arrival, has shown encouraging signs of health, including swimming, eating, and responding to stimuli. Veterinarians have noted that both heads possess active brains and the hatchling is exhibiting normal behavior.

Specialists are monitoring the animal’s appetite, growth, and motor coordination. To better understand the hatchling’s internal anatomy, veterinarians plan to use X-rays and CT scans once the turtle is larger to determine how much the two heads share internal organs and anatomical structures. Zach Mertz, CEO of New England Wildlife Centers, observed behavioral differences, noting that the left head appears to have a ‘greater personality.’

This discovery is significant as diamondback terrapins are considered a threatened species in Massachusetts. The Cape Cod Wildlife Center noted that this is the third case of this anomaly to arrive at the center within the last six years.

## Timeline

### 2026-09-30: Cape Cod: Two-headed turtle hatchling discovered

A rare two-headed Malaclemys terrapin turtle was discovered on Cape Cod. Despite its unusual anatomy, the hatchling is eating and swimming while specialists monitor its development.

2 sources. https://clstr.news/cluster/cape-cod-two-headed-turtle-hatchling-discovered

### 2026-09-22: Diamondback terrapin with two heads discovered in Massachusetts

A rare two-headed diamondback terrapin hatchling, weighing 5.2 grams, was discovered in Wellfleet, Massachusetts, and is receiving specialized care at the Cape Wildlife Center.

3 sources. https://clstr.news/cluster/two-headed-diamondback-terrapin-discovered-on-cape-cod-1

### 2026-09-20: Two-headed diamondback terrapin discovered on Cape Cod

A rare two-headed diamondback terrapin was discovered in Wellfleet, Massachusetts, and is being monitored by wildlife experts at the Cape Cod Wildlife Center.

2 sources. https://clstr.news/cluster/two-headed-diamondback-terrapin-discovered-on-cape-cod

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Cite as: Two-headed diamondback terrapin discovery on Cape Cod. CLSTR, https://clstr.news/situations/two-headed-diamondback-terrapin-discovery-on-cape-cod