Robust, heavy‑bodied requiem shark with a broad, blunt snout and small eyes. Dorsum grey to slate‑brown, fading abruptly to pale ventrum; fin tips dusky in juveniles. First dorsal large and triangular, origin roughly above or just behind pectoral insertions; second dorsal low but broad. Caudal fin asymmetrical with strong ventral notch. Teeth wide‑based, triangular and strongly serrated—adapted for cutting bone. Adults usually 2.1 – 3.2 m total length (TL) and 100 – 230 kg; maximum verified 3.8 m, 316 kg. Females grow larger than males. Neonates 65 – 75 cm TL show darker tail margins and faint lateral band.
Males 2.3 m; females 2.5 m (max 3.8 m)
110 – 230 kg
≈ 32 yr
Deficient Data
Deficient Data
Males ≈ 14 yr / 210 cm TL; females ≈ 18 yr / 230 cm TL
Biennial; mating offshore late dry season, parturition early wet season in river mouths
1 – 13 pups (mean 8)
Robust, heavy‑bodied requiem shark with a broad, blunt snout and small eyes. Dorsum grey to slate‑brown, fading abruptly to pale ventrum; fin tips dusky in juveniles. First dorsal large and triangular, origin roughly above or just behind pectoral insertions; second dorsal low but broad. Caudal fin asymmetrical with strong ventral notch. Teeth wide‑based, triangular and strongly serrated—adapted for cutting bone. Adults usually 2.1 – 3.2 m total length (TL) and 100 – 230 kg; maximum verified 3.8 m, 316 kg. Females grow larger than males. Neonates 65 – 75 cm TL show darker tail margins and faint lateral band.
Coastal marine (< 100 m), turbid estuaries, river mouths and upper freshwater reaches — recorded 80 km upriver (Río Tempisque). Adults forage along continental shelf and offshore islands (Cocos, Murciélago); juveniles prefer low‑salinity mangrove creeks and embayments.
Apex predator consuming teleosts (tarpon, snook), rays, smaller sharks, dolphins, turtles and carrion; opportunistically feeds on domestic animals in river systems.
Social Structure & Behaviour
Activity pattern: crepuscular; peaks at dusk/dawn hunting along salinity fronts.
Group size: generally solitary; loose aggregations (5–15) at river mouths during shrimp runs.
Movements: tide‑dependent upstream excursions; offshore migrations along continental shelf during dry season.
Communication: threat display—arched back, lowered pectorals, rapid zig‑zag swim toward intruder.
Special behaviours: uses low‑frequency electrosensory bursts to detect struggling fish in zero‑visibility water; powerful jaw pressure (> 5 000 N) crack turtle carapace.
Can survive full freshwater for weeks; one tagged female swam 120 km up Río San Juan.
Exhibits seasonal upstream migrations synchronized with mullet and snook spawning runs.
Electro‑reception less sensitive than hammerheads but enhanced lateral line detects struggling prey in murky water.
Females show natal philopatry—returning to same river basin to pup.
Responsible for majority of confirmed Costa‑Rican shark‑bite incidents (mainly in turbid estuaries).
Native
Decreasing
