Jack Anderson wrote:
All watersnakes are moccasins, but only cottonmouths are poisonous. This
seems to confuse people.

I believe you have it backwards. My reading makes it look as if
'moccasin' is the common term for the genus _Agkistrodon_, a class of
venomous snakes including both cottonmouths (water moccasin) and
copperheads (and some other species not relevant to NC). "Water
moccasin" is basically an english-language rendering of the species
name _Agkistrodon piscivorus_ (although 'fish-eating viper' would be
more correct and sounds waaay cooler - which of course is the
cottonmouth. It is confusing!

Therefore, it would be more correct to say that all moccasins are
venomous, but not all watersnakes are moccasins, and not all moccasins
are watersnakes.

http://www.emedicine.com/emerg/bynam...-moccasins.htm

and

http://www.tsha.utexas.edu/handbook/...s/MM/tdm1.html

The latter reference does say "The term water moccasin has been broadly
used to refer to all water snakes, but only the cottonmouth is
poisonous," and that mis-understanding is really the issue we are
dealing with here.

Thanks! I didn't realise that water moccs (cottonmouths) and
copperheads were in the same genus (although I'm sure my husband has
told me that many times

- Susan