Sharks

Class Chondrichthyes skeletons made up entirely of cartilage cartilage contains thousands of minute prisms containing mineral that strengthens bones (hydroxyapatite) distinctive teeth, highly resistant to decay

Order Carcharhiniformes “Ground Sharks” nictitating eyelids present mouth behind front of eyes five pairs of gill slits anal fin present

Family Carcharhinidae head “normal” without lateral expansions first dorsal fin originates in front of pelvic fins anal fin trailing margin strongly concave

Tiger Shark (Galeocerdo cuvier) snout very short, bluntly squared-off upper lobe of caudal fin very long, sharply pointed pigmentation pattern: dark spots/vertical bars on back and flanks

Tiger Shark (Galeocerdo cuvier) electromagnetic receptors, Ampullae of Lorenzini lateral line reads vibrations in water, movement of animals nearby 2nd most attacks on humans, behind great white

Family Sphyrnidae head with lateral, canard-like extensions pelvic fins triangular

Scalloped Hammerhead (Sphyrna lewini) head,hammer-narrow and broadly arched with prominent indentations at each nare and the midline pelvic fins triangular first dorsal fin origin over or slightly behind pectoral axil

Scalloped Hammerhead (Sphyrna lewini) tends to form huge schools hammer enhances senses of smell, electroreception, lift and maneuverability prevents 3D vision and jaw protrusion