The ‘fisheaters’ are the largest of the Agkistrodon genus, with adults known to exceed 31 in length. There is, however, a record exists showing the largest recorded specimen of a cottonmouth snake to be 74 inches in length, based on a specimen caught in the Dismal Swamp region and given to the Philadelphia Zoological Garden.
The venom of the cottonmouth is far more toxic than that of the copperhead viper, since it contains a higher concentration of a cytotoxic venom that destroys tissue. Deaths are rare, but the bite can leave scars, or in more severe cases, require amputation.
It may cause an anaphylactic reaction in a bitten individual, but the bite can be effectively treated with CroFab antivenom.