Skeleton and muscle

shark skeleton.jpg

Dr. Julius Csotonyi 
for Sharks4Kids

Sharks, rays, skates and chimaera have a skeleton made of cartilage. This strong, but flexible connective tissue allows for increased movement. It's also less dense ( weighs less) than bone, which helps sharks stay afloat and use less energy to move. 

shark muscle .png

Dr. Julius Csotonyi 
for Sharks4Kids

Sharks have two types of muscle- red and white. Red muscle is slow contracting and helps the shark swim a long time (marathon). It requires an oxygen rich environment ( good blood supply) and works by breaking down fat in the shark’s body. White muscle is relatively fast contracting and helps with bursts of speed ( sprinting). It uses energy created from the breakdown of sugars ( glycogen) in the body.