Snakes

External Anatomyno limbsnostrilsno external ears no eyelids scales - of various size depending on body location

(for ID - "keeled" or not keeled)anal shield - denotes boundary of trunk & tail

(for ID - anal plate divided or not)

Internal Anatomyonly one lungno urinary bladdermany vertebrae/ribsno sternum (breastbone)very linear digestive tract

Snakes exhibit the concept of "Reduction"

they have lost several anatomical features typical

to other vertebrates:

no earsno urinary bladderno limbsno left lungno sternum

Sensesvision - poorhearing - poorsmell - excellent

forked tongue - Jacobson's organs (roof of mouth)heat - some snakes can detect body heat = "Pit Vipers"

they have pits or holes around mouth that senseIR (body heat) (warm blooded prey)

Killing their food: (all snakes are carnivorous)1. catch & swallow (garter snake, hognose)2. squeeze to death "asphyxiate" the constrictors

(boas, pythons, kingsnakes)3. poison & swallow (rattlesnake, cobra)

Poisonous Snakes:cobras, coral snake, sea snakes …….types of venom:

neurotoxinhemotoxin

snake bite? antivenom shot

Illinois' Poisonous snakes:Water Moccasin (Cottonmouth)CopperheadTimber RattlesnakePygmy Rattlesnake

(swamp rattler or massasagua)

Cottonmouth

Timber Rattlesnake

Copperhead

Practice Quiz: Snakes

Skull Adaptations - snakes have a very movable or "Kinetic" jaw

jaw bones unhinge and dropfront ligament - R/L halves

thrust forward independentlyteeth slant backwards

BirthingOviparous - lay eggs (most snakes)Ovoviviparous - retain eggs in body - attached to yolk sacViviparous - live birth

Largest Snake ever officially recorded:an Anaconda, captured & measured in 1944South America - Orinoco River37 1/2 feet! estimated to weigh nearly 600 pounds!

Illinois Non-Venomous Snakes

Garter Snake DeKay’s Brown Snake

Northern Water Snake

Black Rat Snake

Prairie King Snake

Western Hognose Snake

Practice Quiz – Ill. Non Venomous Snakes