The Copperhead or “highland moccasin” (Agkistrodon contortrix) may reach a length of 20 to 36 in. (51-90 cm). Its record length is believed to be a little less than 4.5 ft. Adults are stout-bodied, venomous snakes. Young specimens have yellow-tipped tails.
Copperheads are not aggressive. When approached, they tend to slip off quietly out of reach. If closely threatened, it may rapidly vibrate its tail and strike viciously. Due to their natural camouflage, this species may be threatened, or suddenly stepped upon, before a hiker realizes what has happened: the snake has no choice but to bite.
It has been my experience after several decades of hiking that copperheads seem to prefer lowlands near swampy areas but may be found in hilly woodlands. Most of the copperheads that I have encountered were active during late afternoon, twilight hours, and darkness.
In early winter they gather at hibernating dens to stay warm and apparently don't wander far off from these dens even during the summer months.
(See also other snakes.)