Diamondback Terrapin (Malaclemys terrapin)
Mature male diamondback terrapin showing a more typical shell colouration and pattern. Note the grey skin with dark freckles; all of Bermuda’s diamondbacks share these same skin characteristics.
Diamondback terrapin swimming among the prop roots of a red mangrove tree in a brackish water pond. In Bermuda these terrapins are highly dependent on mangrove fringed ponds for their survival. While their former range across the Island is unknown, they are now restricted to only 2 such ponds.
Diamondback terrapins (Malaclemys terrapin) have been listed as a globally near threatened species by the International Union for Conservation of Natural Resources (IUCN). Their status (which varies from state to state) on the east coast of the United States (where this species is endemic) ranges from endangered to a species of special concern. Massive over-harvesting for food consumption in the late 19th and early 20th centuries lead to huge declines in the North American populations, which continue to be affected by habitat loss, predation, crab trapping activities and commercial harvest for human consumption.
Bermuda’s Diamondback Terrapin Project began in 2007 in response to the need to fill an enormous gap in our knowledge of a species that had been recently been added to our native fauna list. The origin of diamondback terrapins on Bermuda was tested using a combination of palaeontologic (fossil, radiometric and palaeoenvironmental) and genetic data. These lines of evidence supported the hypothesis that these terrapins are relatively recent (between 3000 and 400 years ago) natural colonizers of Bermuda, most probably having arrived via the Gulf Stream current. They are quite unique in that they represent the second naturally occurring non-marine reptile that still survives here - the other being the endemic Bermuda skink. Scientist studying their island ecology have provided sufficient information to the Department of Environment and Natural Resources that this species was added to the list of species protected under the Bermuda Protected Species Act in late 2011.
Learn More:
Protected Species Recovery Plan for the Diamondback Terrapin (Malaclemys terrapin) in Bermuda. (Outerbridge, 2013)
Occurrence of diamondback terrapins on Bermuda: native or introduced? (Davenport et al., 2005)
Introduced delicacy or native species? A natural origin of Bermudian terrapins supported by fossil and genetic data. (Parham et al., 2008)
Diamondback terrapin foraging behaviour. (Outerbridge & Davenport, 2013)
Ecological assessment of diamondback terrapins on Bermuda. (Outerbridge et al., 2016)
Restricted diet of a native vulnerable turtle on the oceanic islands of Bermuda (Outerbridge et al., 2017)
Post-emergent movements and survivorship of diamondback terrapins in Bermuda: the role of predation by herons. (Outerbridge et al., 2018)