Snakes

External Anatomy no limbs nostrils no 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 Anatomy only one lung no urinary bladder many vertebrae/ribs no sternum (breastbone) very linear digestive tract

Snakes exhibit the concept of "Reduction" they have lost several anatomical features typical to other vertebrates: no ears no urinary bladder no limbs no left lung no sternum

Senses vision - poor hearing - poor smell - 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 sense IR (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: neurotoxin hemotoxin snake bite? antivenom shot

Illinois' Poisonous snakes: Water Moccasin (Cottonmouth) Copperhead Timber Rattlesnake Pygmy 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 drop front ligament - R/L halves thrust forward independently teeth slant backwards

Birthing Oviparous - lay eggs (most snakes) Ovoviviparous - retain eggs in body - attached to yolk sac Viviparous - live birth

Largest Snake ever officially recorded: an Anaconda, captured & measured in 1944 South America - Orinoco River 37 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