Slender, small‑to‑medium reef shark distinguished by conspicuous white tips on first dorsal and upper caudal fins. Snout short, broad and blunt; eyes large, oval with vertical pupil. Dorsum grey‑brown, often with faint dark speckles; belly whitish. First dorsal origin well behind pectoral rear tips; second dorsal and anal low but elongated. Caudal fin strongly notched with white‑tipped upper lobe. Adults average 1.3 – 1.6 m total length (TL), maximum ~2.1 m; mass 18 – 30 kg. Dermal denticles arrow‑shaped giving rough texture. Sexes similar, females slightly longer; males possess claspers.
Males 1.4 m; females 1.5 m
18 – 30 kg
~25 yr
Data deficient
Data deficient
Males ≈ 8 yr / 105 cm; females ≈ 9 yr / 110 cm
Biennial; mating/parturition March – May in Eastern Tropical Pacific
1 – 6 pups (mean 3)
≈ 12 mo
Slender, small‑to‑medium reef shark distinguished by conspicuous white tips on first dorsal and upper caudal fins. Snout short, broad and blunt; eyes large, oval with vertical pupil. Dorsum grey‑brown, often with faint dark speckles; belly whitish. First dorsal origin well behind pectoral rear tips; second dorsal and anal low but elongated. Caudal fin strongly notched with white‑tipped upper lobe. Adults average 1.3 – 1.6 m total length (TL), maximum ~2.1 m; mass 18 – 30 kg. Dermal denticles arrow‑shaped giving rough texture. Sexes similar, females slightly longer; males possess claspers.
Shallow coral and rocky reefs (1 – 65 m), ledges, caves and surge channels; in Costa Rica abundant at Isla del Coco, Isla del Caño, Murciélago Archipelago and rocky points of Golfo Dulce. Often rests in groups inside caves by day.
Nocturnal mesopredator feeding on benthic bony fishes (parrotfish, squirrelfish), octopus, spiny lobsters and crustaceans; hunts by wedging into crevices using slender body.
A. Social Structure & Behaviour
Activity pattern: nocturnal hunter; diurnal resting in caves, often stacked in groups.
Group size: solitary while feeding; daytime groups 5 – 25 in shared shelters.
Movements: high site fidelity to specific caves; home range < 2 km².
Communication: gentle nudges and body contact maintain resting order; threat yawns toward intruders.
Special behaviours: spirals into tight crevices chasing prey; employs suction to extract octopus.
Can pump water over gills while stationary, allowing hours‑long rest in low‑oxygen caves.
Often piles atop one another in “shark stacks” of 20 + individuals at popular dive spots.
Uses highly sensitive electroreceptors to detect prey hidden under coral heads.
Night dives at Cocos reveal cooperative hunting with giant moray eels flushing fish from crevices.
One of the few sharks that can bend sharply, enabling entry into narrow reef holes.
Native
Decreasing
Slender, oceanic requiem shark with a notably silky‑smooth skin created by densely packed dermal denticles. First dorsal fin moderately tall, origin behind pectoral free tips; second dorsal possesses a long free rear tip. Pectorals long, narrow, falcate. Snout long and rounded; eyes large with nictitating membranes. Colour uniform dark bronzy‑grey above, white below; no distinct fin markings except faint dusky tips in juveniles. Adults average 2.2–2.6 m TL (maximum 3.5 m) and 150‑170 kg. Teeth: upper narrow, serrated; lower slender, semi‑erect. Sexual dimorphism minimal—females slightly larger, males with claspers.
