Cottonmouth, Agkistrodon piscivorus

Snakes are amongst the most feared of aU creatures simply because a handful of species are lethal to humans. It is perhaps a forhmate quirk of evolution that snakes strike fear into us, because this means that we leave them alone. On the other hand some harmless snakes, for example the Common Water Snake (Nerodia sipedon) from north America, are killed because they look like dangerous species (in this case the dreaded Water Moccasin or Cottonmouth Agkistrodon piscivorus)). This is an unfortimate quirk of evolution, because the Brown Water Snake has evolved to mimic the dangerous Water Moccasin in the hope of frightening away potential predators. The outcome, however, as far as humans are concerned, is quite the opposite. 

In cottonmouths (Agkistrodon piscivorus), from Texas, mercury tissue concentrations were higher in males than females for kidney and liver one male 96.3 cm in length had 8.6 mg Hg/kg liver FW - the highest mercury concentration ever reported for a serpent. 

Corn snake, Elaphe guttata, 445 Cottonmouth, Agkistrodon piscivorus, 435 Garter snake, Thamnophis sirtalis, 118,... 

Kardong, K. V., 1982, Comparative study of changes in prey capture behavior in the cottonmouth (Agkistrodon piscivorus) and Egyptian cobra (Naja haje), Copeia 1982 337-343. 

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