Groups of Reptiles

Groups of Reptiles

• There are four groups of reptiles1. Turtles and Tortoises2. Crocodilians3. Tuataras4. Lizards and Snakes

Turtles and Tortoises• Have two characteristics that make them different

from other reptiles– Have a hard shell that covers their body– A spine that is fused to the top of their shell

• Most can pull their head and legs into the shell to avoid predators

• Lay eggs in the ground but DO NOT care for their young

• Lack teeth– Have jaws covered in hard plates– Many are herbivores– Some are carnivores (snapping turtle)

Turtles vs. TortoisesTurtles

• Live in water• Have a streamlined shell that

allows rapid movement in water • The shell has two parts

– Carapace = the top part of the shell– Plastron = the bottom part of the

shell– Shell provides the support for all of

the muscles attachments in the torso

Tortoises

• Live on land• Have a dome shaped shell

Tuataras• Only two living species – Found in New Zealand

• Look like lizards, but are a distinct group of ancient reptiles

• Are called living fossils because they have survived nearly unchanged for a 150 million years

• Are more active at low temperatures– Feed at night

Crocodilians

• Includes crocodiles, alligators, caimans, and gavials

• Crocodilians can grow to be very large

Crocodilian Feeding

• Crocodilians are aggressive carnivores• Usually capture prey by ambush– Floats just under the water’s surface and waits for

prey to drink from the water– The crocodilian explodes out of the water, seizes

its prey and hauls it into the water to be drowned and eaten

Crocodilian Body Structure

• Its body is well adapted to hunting – Its eyes are high on its head, and nostrils are

located on top of its snout so it can see and breathe while nearly submerged in water

– Have very sharp teeth to help them tear apart their prey

Crocodilian Reproduction• Unlike other reptiles crocodilians care for their

young– Example: Alligators• Mothers build nest with vegetation to protect the eggs• Once the eggs hatch the mother tears apart the

vegetation to free the hatchlings• They remain under the mothers protection for a year

Lizards and Snakes

• Snakes are close relatives of lizards• Snakes and lizards have many features in

common– Periodic molting– A jaw that is loosely attached to the skull• Allows mouth to open wide to accommodate large prey

Lizards• Common lizards are: Geckos, anoles, and horned

lizards • Most lizards are carnivores– A few are herbivores

• Lizards are typically found in tropical forests and deserts

• Many are fast runners and good climbers• Are usually small (less than 30cm) • Have external ears and eyelids• Some are legless• They have a tail that can break off– Allows them to escape from predators

Snakes: Eating Habits

• Snakes swallow their prey whole– A snake’s jaw is very flexible because the jaw has five

points of movement • Some snakes are constrictors – They wrap their body around their prey and squeeze

tighter and tighter until they suffocate their prey• Examples: Boa Constrictors, pythons

• Other snakes kill their prey with venom– Modified salivary glands produce venom that is

injected into the victim through their grooved or hallow teeth

– Examples: Rattle Snakes, cobras, vipers

Snake: Reproduction

• Most snakes lay eggs– Some mother snakes may stay with the eggs until

they hatch

• Some snakes are ovoviviparous and give birth to live young