They are mostly bottom-dwellers. The sound bounces off the object and some returns to the whale. The whale interprets this returning echo to determine the object's shape, direction, distance, and texture. Bats also use echolocation. Reptiles are ectothermic.
Most sharks are ectothermic.
Each gill slit is covered by frills of skin, hence its name. Its teeth have 3 cusps on a wide base. It has an anal fin and one small dorsal fin. The pectoral fins are short and rounded. The frilled shark is viviparous, giving birth to 8 to 12 live young in a litter after a gestation period of about 1 to 2 years.