Elasmobranchii (sharks and rays) > Carcharhiniformes
(Ground sharks) > Sphyrnidae
(Hammerhead, bonnethead, or scoophead sharks)
Etymology: Sphyrna: Probable misspelling of sphyra (Gr.), hammer, referring to their hammer-shaped heads. (See ETYFish).
Environment: milieu / climate zone / depth range / distribution range
Marine; benthopelagic. Tropical; 17°N - 5°S, 19°W - 13°E
Eastern Atlantic: Senegal to Congo. Not in Compagno's 1999 checklist (Ref. 35766).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 300 cm TL male/unsexed; (Ref. 244)
A coastal-pelagic shark. Feeds on fishes, especially bony fishes, and also benthic and epibenthic cephalopods. Viviparous, with 24 to 28 young in a litter. Size at birth about 30 to 32 cm.
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Viviparous, placental (Ref. 50449).
Compagno, L.J.V., 1984. FAO Species Catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 2 - Carcharhiniformes. FAO Fish. Synop. 125(4/2):251-655. Rome: FAO. (Ref. 244)
IUCN Red List Status (Ref. 125652)
Threat to humans
Fisheries: subsistence fisheries
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Preferred temperature (Ref. 123201
): 24.4 - 28, mean 26.7 °C (based on 64 cells).
Phylogenetic diversity index (Ref. 82804
= 0.5029 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00347 (0.00157 - 0.00767), b=3.12 (2.93 - 3.31), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 4.5 ±0.54 se; based on food items.
Resilience (Ref. 120179
): Low, minimum population doubling time 4.5 - 14 years (Fec=24).
Fishing Vulnerability (Ref. 59153
): Very high vulnerability (90 of 100).