Sharks are very important to habitat health as they mainly take advantage of sick or injured sea creatures as a source of food. They are very particular about what they eat. Each shark species is specially adapted for eating certain kinds of marine animals. Sharks face some big challenges in their environment. Sharks can be caught accidentally in fishing nets or lines, causing them to be injured and discarded as waste. Marine debris, or any garbage that ends up in the ocean instead of the landfill or recycling center, is also a problem. Our conservation efforts upstream in St. Louis do make a difference, since our rivers and streams all eventually connect to the ocean. Disposing of waste properly and avoiding use of plastic bags are some ways that St. Louisans can help. See our info on sustainable seafood choices to see how you can help.
Since sharks don't have bones, their teeth are basically big, modified scales. Their teeth aren't set firmly into their jaw or gum tissue. They are formed inside a membrane inside the jaw.
The "ampullae of Lorenzini" are tiny black dots on the chin of the shark that help it sense electromagnetic fields in the ocean, such as stingrays hiding under the sand.
Sharks have a lot of sensitivity in their mouths and have been found mouthing drift wood in the middle of the ocean.
No Bones About It
A shark's skeleton is made of cartilage - the same thing that makes up your ears and the tip of your nose. Cartilage is lighter and more elastic than bone.
Most sharks have eight fins: two dorsal fins on top; two pectoral fins on the bottom front; two pelvic fins on the bottom back; an anal fin behind the pelvic fins and the tail, or caudal fin.
Bonnethead sharks have eyes located far out on either side of their hammer-like heads, giving them large fields of vision.
Gills & Spiracles
Like other fish, sharks breathe with the help of gills. Bamboo sharks have an adaptation to help them breathe while resting on the bottom of the ocean. These openings located near the eyes are called spiracles. Instead of sucking in sandy water through their gills, they can pull clear water in through their spiracles.
Bamboo and nurse sharks have sensory organs called nasal barbels that help them locate food.