A rather quick-tempered species (3), the Mississippi green watersnake is known to strike out and bite when it is provoked, and may exude a potent musk (3) (4).
It is thought that the Mississippi green watersnake avoids the high temperatures throughout the summer by becoming mostly nocturnal and spending a large proportion of its time in its aquatic habitat (3). Diurnal activity has also been recorded throughout the summer in other parts of this species’ range (4) (5).
The diet of the Mississippi green watersnake consists mostly of fish (3) (4), especially mosquitofish (Gambusia species) and sailfin mollies (Poecilia latipinna) (3). This species may also take amphibians and invertebrates, such as crayfish (4). While hunting, it swims underwater with its mouth open, turning its head from side to side (3) (4).
There is very limited information available on the reproductive biology of the Mississippi green watersnake, although in the southern coastal part of its range, mating is thought to occur in early to mid-April. Litters of between 9 and 34 young usually appear between mid-July and mid-September (3).