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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