as a follow up on the zoological references..
the copper head is related to the cottonmouth and water moccasin

http://www.ces.ncsu.edu/gaston/Pests/reptiles/copperhead.htm
http://www.snakesandfrogs.com/scra/snakes/copperh.htm

http://www.wf.net/~snake/moccasin.htm
http://en.wikipedia.org/wiki/Agkistrodon_piscivorus