RATTLESNAKES

http://wildlifediscoveries.blogspot.com 

There are approximately thirty species of rattlesnake, with numerous subspecies. They receive their name for the rattle located at the end of their tails. The rattle is used as a warning device when threatened. The scientific name Crotalus derives from the Greek, meaning "castanet". The name Sistrurus is the Latinized form of the Freed word for "tail rattler" and shares its root with the ancient Egytian musical instrument, the sistrum, a type of rattle. Most rattlesnakes mate in the spring. All species give live birth, rather than laying eggs. The young are self-sufficient from birth. Since they do not need their mother after birth, the mother does not remain with her young. However, at least one captive study has demonstrated that females and the neonates show some level of affinity for each other's company and will cross barriers to reunite if separated. Contrary to popular myth, rattlesnakes are not deaf. In fact, the structure of their inner ears is very much like that of other reptiles. They do, however, lack external ears. Sound (whether from air or ground vibration) is transmitted to the snake's inner ear via bone and muscle.

Rattlesnakes consume mice, rats, small birds and other small animals. They subdue their prey quickly with a venomous bite as opposed to constricting. The venom will immediately stun or kill typical prey. Rattlesnake venom can kill in 20 seconds, but a rattlesnake will not follow prey that does not quickly succumb to the venom and attempts to escape. Rattlers are known to strike at distances up to two-thirds of their body length.

Although many kinds of snakes are oviparous (lay eggs), rattlesnakes are ovoviviparous - the females retain the eggs in her body and they hatch as they are laid or soon afterwards: or viviparous (give birth to live young). Baby snakes are ready to go as soon as they are hatched or born. There is little to no parental care of the newborn snakes.

The rattle is composed of a series of nested, hollow which are actually modified scales from the tail tip. Each time the snake sheds its skin, a new rattle segment is added. They may shed their skins several times a year depending on food supply and growth rates. Newborn rattlesnakes (pre-button) do not have functional rattles; it is not until after they have shed their skin for the first time that they gain an additional bead, which  beats, against the first bead, known as the button, to create the rattling sound. Adult snakes may lose their rattles on occasion, but more appear at each molting. If the rattle absorbs enough water in wet weather, it will not make noise.

read more at Wild Life Discoveries http://wildlifediscoveries.blogspot.com