Completar Frases AnimalsVersión en línea What do you know about animals? por Kim Ngân 16 Nguyễn Thị 1 22 5 7 fish 12 420 39 whale Sharks are a group of belonging to the class Cartilaginous fish , hydrodynamic body easily diverging , with to gill slits along each side or near the head ( the first slot behind the eye is called the spiracle ) , skin with many spines . small cover the body against parasites , the rows of teeth in the mouth can grow back . Sharks range from the size of a hand , from Euprotomicrus bispinatus , a seabed fish just centimeters long , to the giant shark ( Rhincodon typus ) , the largest fish at meters long . ( ft ) is about the size of a whale but only eats plankton , squid , and some other small fish . The bull shark ( Carcharhinus leucas ) is also best known for its ability to swim in both freshwater and saltwater , [ 1 ] even in deltas . Sharks are thought to have appeared more than million years ago , before the time of the dinosaurs .