Sand Tiger Sharks are the only sharks known to come to the surface and gulp air. They store the air in their stomachs, which allows them to float motionless in the water while hunting.

Sand Tiger Shark   © Mark Fox

This Shark is not related to the Tiger Shark (Galeocerdo cuvier) however, it is a cousin of the Great White Shark (Carcharodon carcharias).
Despite its fearsome appearance and strong swimming ability, it is a relatively docile and slow-moving shark that will only attack a human when threatened.

The Sand Tiger Shark (Carcharias taurus), also called Grey Nurse Shark, Spotted Ragged-tooth Shark, or Blue-nurse Sand Tiger is a species of shark that inhabits the sandy shores of subtropical and temperate waters around the globe from Japan, Australia, South Africa, the Mediterranean to the east coasts of North and South America.

During the day, these sharks take shelter near rocks, overhangs, caves and reefs often at relatively shallow depths (less than 20m). This is the typical environment where divers encounter sand tigers. However, at night they leave the shelter and hunt over the ocean bottom.

Sand tigers hunt by stealth for which they have developed their very own technique to optimise this method.
Since the shark is denser than water and lacks a swim bladder it needs to keep moving to avoid sinking. Instead, this species comes to the surface and gulps air, which it holds in its stomach.
This allows the shark to maintain near-neutral buoyancy and hover motionless in the water.

The Sand Tiger Shark is the only known shark species to use this method to achieve buoyancy in the water.

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