TROPICAL CROCODILIANS 3-31-05

Often the dominant predators in their habitat.

Could there be a more inviting sign?

Alligator (l) & Crocodile (r) – Note the rounded snout of the alligator and the pointed snout of the crocodile.

Alligator (top) and Crocodile (bottom) – Note that teeth are barely visible in alligators and obvious in crocodiles, especially the lower 4th tooth that actually fits into a slot in the upper jaw.

Crocodilians have cartilage (formerly bones) – called gastralia - in the belly that protect the vital organs from attacks from below.

Crocodilians have glands (r, grey protrusion) used in communication; they also have a number of postures they use to communicate (l), as well as bellows.

Crocodilians have dermal bones, called osteoderms, inside the dorsal scales that make their backs almost impenetrable; Amerindians use the osteoderms for jewelry.

Crocodilians often pick up items that stay in the stomach for help in grinding. These items are called gastrolyths. Here is a rock taken from an old caiman in Venezuela. Note how smooth it is.

Unlike other reptiles (except turtles), crocodilians have a single penis.

Sexing a crocodilian: Insert the finger into the cloaca and press forward. If male, can feel a hard “ridge;” if female, just soft tissue.

Caimans are the common crocodilian of the Neotropics.

Spectacled Caiman, Caiman crocodilus.

Morelet’s Crocodile, Crocodilus moreletii - Belize

American Crocodile, Crocodilus acutus – S Florida throughout the Caribbean.

Nile Crocodile, Crocodilus niloticus – Africa – in photo on right, the croc is thermoregulating.

A big salty, Crocodilus porosus

The salty getting a sniff of air

Can you see the Morelet’s Crocodile?

Crocodile skin is easily recognized by having a pore in each scale (note the white dots).

Alligator skin has no pores and the belly scales (seen here) are smooth.

Caiman skin has osteoderms in virtually all scales. When the skin dries, it has little crinkles around the osteoderm.

The very rare False Gharials, Tomistoma schlegelii, live in Indonesia and are resolute piscivores. The snout is narrow to enhance catching their prey as they quickly slash from side to side.

Gharial, Gavialis gangeticus – N India & W SE Asia - skull – also a piscivore.

And then there is the entrance door to Gatorland, FL.

An you think you’ve had bad days! From National

Geographic.

Cloaca