Two-Headed Sea Turtle Hatched in Costa Rica

OSTIONAL, Costa Rica, December 1, 2005 (ENS) - A two-headed olive ridley sea turtle hatchling crawled out of its egg last week at Ostional, a village on the Pacific coast of Costa Rica. It is one of three places in the world where synchronized emergences of thousands of nesting female turtles, called arribadas, can still be seen.

Olive ridleys, Lepidochelys olivacea, like all species of marine turtles, are endangered.

The two-headed hatchling was born in good health - both heads were emerging above the water surface to breathe. “This is something that no one here has seen in more than 50 years of working with sea turtles,” said Melvin and Olger Chavarría, owners of a local lodge who found the hatchling November 21.

The two-headed turtle caught the attention of WWF, the global conservation organization, which says deformations of this sort can be associated with contaminants, increased temperatures possibly resulting from climate change, or other causes.

“The specific cause of this case of bicephalism is not known," said Carlos Drews, WWF Regional Coordinator for Marine Turtles. "But, increased temperatures as an outcome of climate change cause drastic modifications to the incubation environment in sea turtle nests."


This two-headed olive ridley turtle was found on the beach at Ostional. Ocean warming or toxic pollutants could be responsible for the mutation. (Photo by Carlos Drews courtesy WWF Central America)
"Similarly," said Drews, "industrial and agricultural contaminants dumped into river channels reach the sea and become incorporated into the food chains, where they can affect sea turtles."

WWF believes that a successful turtle conservation program requires scientific backing at international, national and community scales. Drews says more information is needed about the number of turtles that are nesting on the beaches, whether the species and their food sources are increasing or declining, on their relationships with other living organisms, and on the presence of anomalies and malformations that may serve as early warning signals for identifying threats.

“We have no idea of the condition of the internal organs of this hatchling, so we cannot estimate its probability of survival. Plus, severe obstacles await it in the sea, mainly fishing nets and fishhooks,” Drews said.

Since its founding in 1961, WWF has supported numerous sea turtle conservation efforts around the world. In order to reduce incidental capture of sea turtles in fishery operations, WWF works on disseminating new fishing techniques such as the use of different baits, the use of circular rather than classic J-fishhooks, and the use of fishhook-removers to free turtles from the hooks.

WWF is working to mitigate global climate change around the world and to reduce ocean contamination in Central America.

“Factors that affect sea turtle embryonic development must be investigated, because the species can serve as indicators for recognizing the impacts of climatic alterations or pesticides and agrochemicals on coastal and marine ecosystems," Drews said. "The alarming condition of sea turtles today points to an urgent need to improve our relationship with the oceans."