Sand Tiger (Ragged-Tooth) Shark

栖息地: Wrecks, ledges, gutters, and caves over the continental shelf; gulps surface air to hover neutrally in the water column

分布范围: Warm temperate coasts of the Atlantic, Indian, and western Pacific oceans, famously the US East Coast, South Africa, and eastern Australia, where it is called the grey nurse shark

习性: Hangs almost motionless in shaded structure by day, mouth slightly agape in a permanent bristle of teeth, drifting among divers with slow tail strokes. The only shark known to gulp and store surface air for buoyancy. Aggregates seasonally at traditional sites for mating and gestation.

食性: Fish including small sharks and rays, hunted mostly at night; the snaggle-toothed jaws are for gripping, not shearing

体型: 通常约 2.5 m; 记录深度可达 3.2 m (total length).

Move slowly through wreck interiors and gutters they occupy, never block a shark's exit, no touching during close drift-bys, and follow local aggregation-site rules on diver numbers and approach distance.

Critically Endangered globally as of 2021. Australia protected its grey nurse populations decades ago after spearfishing collapses; recovery everywhere is slow arithmetic against a two-pup reproductive rate.