Post by Ceratodromeus on May 22, 2015 22:49:39 GMT 5
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Subfamily: Natricinae
Genus: Natrix
Species: N.natrix
Description
The grass snake is a dull green in color, with yellow, white, and black patterning. Black banding can be found on the nape of the neck, as well as the lower jaw. Such banding differs between individuals within the species. This snake is relatively large, with the length of males ranging from 47-96cm, averaging a total length of 80cm. Females are larger, as the species is sexually dimorphic, ranging from 60-112cm{1} Weights range anywhere from 150-350g{3}.
Geographic range
These snakes can be found throughout mainland Europe, ranging from Italy to Germany. They stick mainly to large bodies of water, where they spend most of their time foraging.
Dietary habits
The diet of the grass snake consists primarily of anurans and bufonids. The European toad, common toad, and marsh frog are all common-place prey animals. Predation on fish, such as the perch( has also been noted{2}.In parts of their geographic range, a slight differentiation in diet can be noted. For example, populations in Italy are known to include more mammalian prey(Microtus, mus, rattus) then, say, populations in England. This supports the notion Natrix natrix is a generalistic predator rather then one that specializes in anurophagy{1}.
Reproduction
Mating occurs in Spring, where these snakes congregate in large 'mating balls', in which there are typically many more males then there are females. The size of the individual was noted to play a crucial factor in mating-- that is, larger males had better chances of reproducing successfully{4}. Eggs are laid in May/ June( seasonality and locale determinant.) and they hatch roughly ten weeks later.
Defensive behaviors
Not being constrictors, nor venomous, the grass snake is rather limited in what it can do defensively. When captured, they will either turn and bite, or discharge a foul smelling liquid from their anal gland; this is commonly referred to as "musking".They do have one more trick up their sleeve, though. If hard pressed,they will "feign death" -- that is, they'll turn themselves upside down and open their jaws, the tongue hangs limply from the jaws. This is to give the perceived threat the idea that the snake is dead, and usually that perceived threat leaves. When it does,the snakes corrects itself and continues on with its life.
References
{1}Filippi, E. R. N. E. S. T. O., et al. "The prey spectrum of Natrix natrix (Linnaeus, 1758) and Natrix tessellata (Laurenti, 1768) in sympatric populations." Herpetozoa 8.3/4 (1996): 155-164.
{2}Reading, C. J., and J. L. Davies. "Predation by grass snakes (Natrix natrix) at a site in southern England." Journal of Zoology 239.1 (1996): 73-82.
{3}Luiselli, Luca, Ernesto Filippi, and Massimo Capula. "Geographic variation in diet composition of the grass snake (Natrix natrix) along the mainland and an island of Italy: the effects of habitat type and interference with potential competitors." The Herpetological Journal 15.4 (2005): 221-230.
{4}Luiselli, Luca. "Individual success in mating balls of the grass snake, Natrix natrix: size is important." Journal of Zoology 239.4 (1996): 731-740.