Cryptobranchus alleganiensis. Source: Wikimedia Commons
Hellbenders, snot otters and devil dogs: these colorful names all belong to the hellbender salamander, a giant North American amphibian.
The hellbender is fast disappearing from its native North American ecosystems, where it acts as a bioindicator of water quality in the rocky, fast-moving water bodies it inhabits. Present in 16 states, the hellbender is now struggling to survive as siltation and pollution put pressure on these fragile habitats.
Divided into two subspecies, the eastern hellbenders, C. a. alleganiensis, and Ozark hellbenders, C. a. bishopi, it is the eastern hellbender that is currently attracting the most attention. This is largely thanks to the U.S. Fish and Wildlife Service, which is investigating the eastern hellbender in order to assess whether it should be given endangered status.
So far, the smoking gun for the decline of the eastern hellbender is human activity. Contamination of water sources, damming of previously fast-flowing rivers, and siltation caused by run-off from development sites are all putting a squeeze on the eastern hellbender. Siltation is of particular concern, since the hellbender breathes through its skin; this is impeded by fine silt in the water, making oxygen uptake difficult. There could be other factors at play, too: temperature and dissolved oxygen must be constant, and prey items must be present in ample numbers; changes in any of these can cause environmental stress in amphibians.
A Pennsylvanian hellbender. Source: George Grall, National Geographic
The U.S. Fish and Wildlife Service has already declared the Ozark hellbender an endangered species. After a 75% drop in numbers, the Ozark hellbender received protected status in 2011. The Ozark Hellbender Working Group has been involved with the conservation of this strictly aquatic subspecies of salamander since the early Naughties, and have a number of species regeneration and habitat restoration projects underway. The St. Louis Zoo is also involved in a project with the Missouri Department of Conservation raising juvenile salamanders in captivity.
Hellbenders can grow up to two feet long, and have a long lifespan, up to 30 years in the wild. The latter is a reason for their decline going unnoticed up until now, since habitat surveys were still recording their presence. However, populations currently being monitored mainly consist of mature individuals, with little or no regeneration taking place.
The National Geographic has more information on the hellbenders' range, efforts to conserve them, and other information and media here.
