crocodilians, lizards, + snakes

exam 4 bio 305

crocadilians

• gavial

• alligator

• crocodile

crocodile vs. alligator

• alligator → even teeth, rounder head

• crocodile → top + bottom teeth show, v shaped head

lizards

• geckos

  • small, agile

  • nocturnal forms

  • adhesive toe pads

• iguanids

  • many new world lizards

• chameleons

  • arboreal lizards of Africa

  • extendible tongue

• skinks

  • smooth scales

• monitors + relatives

  • get large

  • arid adapted

• amphisbaenians

  • burrowing

  • usually legless

• CT lizards

  • five lined skink

  • Italian wall lizard

• venomous lizards

  • neurotoxins

  • pain, edema + weakness

  • store fat in tails

snakes

• ~3,400 spp (~600 venomous)

• 120 spp in USA (~21 venomous)

• can eat prey several times their own size

• two halves of lower jaw are loosely joined

• non movable eyelids

  • most have poor vision

  • arboreal snakes are exception

• lack external ears

• mainly use chemical senses with forked tongue (Jacobson’s organ)

• pit vipers → sense heat

• ~8,000 snake bites each year

• nonvenomous snakes use constriction or biting + swallowing

CT snakes

• eastern ratsnake

• smooth green snake

• eastern hognose

• eastern worm snake

• eastern garter

• northern ringneck

• eastern milk snake

• northern water snake

• northern black racer

• northern copperhead

• timber rattlesnake