Bicephalic Diamondback Terrapin Hatched in U.S.

A rare two-headed diamondback terrapin has hatched, with veterinarians monitoring its health and behavior.

Updated on Sept. 28, 2026 in Reptiles

Bold vector editorial illustration of a two-headed diamondback terrapin hatchling perched on a river stone, representing a rare biological occurrence. — Veterinarians in the United States are closely monitoring a rare two-headed diamondback terrapin that recently hatched and is currently under observation. AI Illustration. Upload story photo >

A diamondback terrapin recently hatched in the United States with two heads. The rare hatchling, which weighs 5.2 grams, is currently under veterinary observation to assess its appetite and movement.

Why it matters

Bicephaly, a rare condition where twins fail to separate during embryonic development, provides a unique opportunity for veterinarians to observe the survival and physiological challenges of such animals.

The bicephalic hatchling weighs 5.2 grams, or approximately 0.01 pounds. Diamondback terrapins typically live up to 40 years in the wild and inhabit coastal salt marshes throughout the Northeastern U.S.

The details

This rare phenomenon occurs inside an egg during embryonic development when a pair of twins fails to fully separate. Veterinary teams are currently monitoring the hatchling's unique behavior and appetite to ensure it receives appropriate care.

Two other bicephalic cases were observed within the last five years.
The hatchling was reported on in September 2026.

Culture Shift

This rare hatching highlights the ongoing interest in rare biological phenomena within the reptile community. It follows a pattern of documented developmental abnormalities in the last five years, reinforcing the fascination with rare mutations.

This development serves as a reminder of the complexity of wildlife development in local coastal ecosystems. It requires no change to daily routines, but emphasizes the need for awareness regarding the native wildlife found in salt marshes.

The takeaway

While bicephaly is a fascinating biological rarity, these animals often face significant physiological challenges throughout their lives. Observational care remains the standard practice for ensuring the well-being of such unique creatures in captivity.