Great Hammerhead (Sphyrna mokarran)

SharkMarineTropical

Overview

The great hammerhead (Sphyrna mokarran) is the largest of the hammerhead sharks, found in tropical and warm temperate seas around the world.

Adults are told apart from the smooth and scalloped hammerheads by the front edge of the head, which is nearly straight with a central notch (it is more curved in the young). They also have a very tall, curved first dorsal fin, and high second dorsal and pelvic fins with deeply concave rear edges. The body is gray to gray-brown above and white below, without conspicuous fin markings.

The largest reported great hammerhead measured 610 cm in total length, but most are much smaller: a common length of 370 cm is given, and the species rarely exceeds 4.5 m. Females are typically slightly larger than males.

Habitat & Range

Great hammerheads are coastal-pelagic and semi-oceanic sharks, found close inshore and well offshore over continental and island shelves, in passes, lagoons and bays, on coral reefs and near seamounts, in marine and brackish water. They have been recorded from 1 to 300 m deep but are most common in shallow coastal water, and they tend to prefer water of 20 °C and warmer.

The range spans the western Atlantic from North Carolina to Uruguay, including the Gulf of Mexico and Caribbean; the eastern Atlantic from Morocco to Senegal and the Mediterranean; the Indian Ocean, including the Red Sea and Persian Gulf; the Indo-Pacific from the Ryukyu Islands to New Caledonia and French Polynesia; and the eastern Pacific from southern Baja California to Peru. In Australia it occurs from Mandurah, Western Australia, around the tropical north to about Sydney.

Diet

The great hammerhead is an active predator with a broad diet — bony fishes such as groupers and sea catfishes, other sharks and rays, crabs, lobsters, squid and other cephalopods — but it prefers stingrays and other batoids when available. Stingray remains were found in the stomachs of over 80% of great hammerheads caught off Natal, South Africa, and one shark found off Florida had 96 stingray barbs lodged in its mouth. It is thought to eat its own kind when food is scarce.

Behavior

Great hammerheads are typically solitary, though they have been seen migrating in groups during summer. They are highly migratory and apparently nomadic: some populations move poleward into cooler water in summer, as off Florida and in the South China Sea, and individuals travel long distances each day.

Human Interaction & Conservation

Great hammerheads are fished commercially and recreationally, and their large fins are highly valued in the Asian fin trade. The species is considered potentially dangerous to people, but few if any attacks can be definitely attributed to it, because the large hammerhead species are hard to tell apart. It is listed as a highly migratory species in Annex I of the 1982 Convention on the Law of the Sea.

IUCN's global assessment lists the great hammerhead as Critically Endangered (2019).

Conservation assessment

Great Hammerhead (Sphyrna mokarran)

Critically Endangered (CR)Matches source

FaunaHub's record matches IUCN's published Red List data for this species (global assessment, 2019), checked 2026-10-09.

Source and dates

Assessed taxon: Sphyrna mokarran
Assessed: 2019, global assessment
IUCN taxon: 39386
Checked by FaunaHub: 2026-10-09, against IUCN's Red List export published 2026-07-28
FaunaHub record: reviewed 2026-06-16

IUCN Red List assessment (2019)

IUCN Red List categories are reassessed over time. FaunaHub is not a conservation authority; check the current assessment before relying on it.

Reproduction & Life Cycle

The great hammerhead gives birth to live young. Gestation lasts about 11 months, pups are born in spring or summer in the Northern Hemisphere at 50–70 cm long in most accounts, and females breed once every two years. Accounts disagree on litter size — from 6 to as many as 50 pups, with 6–42 and 13–42 most often given — and on whether the young are nourished through a yolk-sac placenta.

Off Australia, males mature at 2.25 m and females at 2.10 m total length; one account gives ages at maturity of 15 years for females and 6 years for males.

Expected life spans of 20–30 years and of about 20 to 40 years are given. The oldest recorded great hammerhead was 44, and another account says the species may live up to 44 years, though one database gives a maximum reported age of 30 years.

Sourced facts

Each value below is traced to the specific reference that states it. Open a row's evidence to see the source, where to look in it, and how firmly it supports the value. Sources checked 2026-10-20.

Sourced facts about the Great Hammerhead, with the reference supporting each
Fact	What the source states	Evidence
Distinguishing traits	Largest hammerhead (family Sphyrnidae). Adult head: front edge nearly straight with a central notch (more curved in young). Very tall, curved first dorsal fin; high second dorsal and pelvic fins with deeply concave rear edges. Gray to gray-brown above, white below; no conspicuous fin markings.The nearly straight, notched front margin of the adult head separates it from the smooth and scalloped hammerheads.	Matches source · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.), Museums Victoria (Fishes of Australia; Bray 2020) — how we know Florida Museum of Natural History (University of Florida) Where Florida Museum: introduction, Biology – Distinctive Features; FishBase: Short description; Fishes of Australia: Summary Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: introduction, Biology – Distinctive Features; FishBase: Short description; Fishes of Australia: Summary Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Museums Victoria (Fishes of Australia; Bray 2020) Where Florida Museum: introduction, Biology – Distinctive Features; FishBase: Short description; Fishes of Australia: Summary Checked by FaunaHub 2026-10-20 Limits Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note.
Geographic range	Circumglobal in tropical and warm temperate seas: western Atlantic from North Carolina (US) to Uruguay, including the Gulf of Mexico and Caribbean; Morocco to Senegal and the Mediterranean; the Indian Ocean; Ryukyu Islands to New Caledonia and French Polynesia; southern Baja California to Peru.The Red Sea, Persian Gulf, South China Sea and East China Sea are also named. In Australia it occurs from Mandurah, Western Australia, around the tropical north to about Sydney. No introduced range is reported.	Matches source · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.), California Academy of Sciences (Eschmeyer's Catalog of Fishes), Museums Victoria (Fishes of Australia; Bray 2020) — how we know Florida Museum of Natural History (University of Florida) Where Florida Museum: Geographical Distribution; FishBase: Distribution; Eschmeyer's Catalog of Fishes: Distribution; Fishes of Australia: Distribution Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: Geographical Distribution; FishBase: Distribution; Eschmeyer's Catalog of Fishes: Distribution; Fishes of Australia: Distribution Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. California Academy of Sciences (Eschmeyer's Catalog of Fishes) Where Florida Museum: Geographical Distribution; FishBase: Distribution; Eschmeyer's Catalog of Fishes: Distribution; Fishes of Australia: Distribution Checked by FaunaHub 2026-10-20 Limits Taxonomic catalogue (online version updated 21 Sep. 2026); distribution is a one-line summary. Museums Victoria (Fishes of Australia; Bray 2020) Where Florida Museum: Geographical Distribution; FishBase: Distribution; Eschmeyer's Catalog of Fishes: Distribution; Fishes of Australia: Distribution Checked by FaunaHub 2026-10-20 Limits Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note.
Habitat	Coastal-pelagic and semi-oceanic: close inshore and well offshore over continental and island shelves, in passes, lagoons and bays, on coral reefs and near seamounts; marine and brackish water; recorded from 1 to 300 m deep, most commonly in shallow coastal water.Tends to prefer water of 20 °C and warmer.	Matches source · FishBase (Froese & Pauly, eds.), Florida Museum of Natural History (University of Florida), Australian Museum, Animal Diversity Web (University of Michigan Museum of Zoology) — how we know FishBase (Froese & Pauly, eds.) Where FishBase: Environment, Biology; Florida Museum: Habitat; Australian Museum: Habitat; ADW: Habitat Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Florida Museum of Natural History (University of Florida) Where FishBase: Environment, Biology; Florida Museum: Habitat; Australian Museum: Habitat; ADW: Habitat Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). Australian Museum Where FishBase: Environment, Biology; Florida Museum: Habitat; Australian Museum: Habitat; ADW: Habitat Checked by FaunaHub 2026-10-20 Limits Short factsheet (updated 10/10/22); no region given for its maturity and litter figures; lists the order as 'Carcharhinidae'. Animal Diversity Web (University of Michigan Museum of Zoology) Where FishBase: Environment, Biology; Florida Museum: Habitat; Australian Museum: Habitat; ADW: Habitat Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
Diet	Active predator with a broad diet: bony fishes (e.g. groupers, sea catfishes), other sharks and rays, crabs, lobsters, squid and other cephalopods; prefers stingrays and other batoids when available. Thought to be cannibalistic when food is scarce.Stingray remains were found in the stomachs of over 80% of great hammerheads caught off Natal, South Africa, and one found off the Florida coast had 96 stingray barbs lodged in its mouth. Off Australia it prefers bottom-living prey such as the Australian cownose ray during the austral summer.	Matches source · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.), Museums Victoria (Fishes of Australia; Bray 2020), Animal Diversity Web (University of Michigan Museum of Zoology) — how we know Florida Museum of Natural History (University of Florida) Where Florida Museum: Food Habits; FishBase: Biology; Fishes of Australia: Feeding; ADW: Food Habits, Other Comments Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: Food Habits; FishBase: Biology; Fishes of Australia: Feeding; ADW: Food Habits, Other Comments Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Museums Victoria (Fishes of Australia; Bray 2020) Where Florida Museum: Food Habits; FishBase: Biology; Fishes of Australia: Feeding; ADW: Food Habits, Other Comments Checked by FaunaHub 2026-10-20 Limits Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note. Animal Diversity Web (University of Michigan Museum of Zoology) Where Florida Museum: Food Habits; FishBase: Biology; Fishes of Australia: Feeding; ADW: Food Habits, Other Comments Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
Body size	Total length up to 610 cm.Typical sizes: common length 370 cm total length; most adults not above 366 cm; rarely exceeds 4.5 m; an average length of 3 m. Females are typically slightly larger than males: males reach at least 341 cm and females 482 to 549+ cm.	Matches source · FishBase (Froese & Pauly, eds.), Florida Museum of Natural History (University of Florida), Museums Victoria (Fishes of Australia; Bray 2020), Australian Museum, Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG), Animal Diversity Web (University of Michigan Museum of Zoology) — how we know FishBase (Froese & Pauly, eds.) Where FishBase: Length at first maturity / Size / Weight / Age; Florida Museum: introduction, Size, Age, and Growth; Fishes of Australia: Quick Facts; Australian Museum: Size Range; Naturalis: Size; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Florida Museum of Natural History (University of Florida) Where FishBase: Length at first maturity / Size / Weight / Age; Florida Museum: introduction, Size, Age, and Growth; Fishes of Australia: Quick Facts; Australian Museum: Size Range; Naturalis: Size; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). Museums Victoria (Fishes of Australia; Bray 2020) Where FishBase: Length at first maturity / Size / Weight / Age; Florida Museum: introduction, Size, Age, and Growth; Fishes of Australia: Quick Facts; Australian Museum: Size Range; Naturalis: Size; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note. Australian Museum Where FishBase: Length at first maturity / Size / Weight / Age; Florida Museum: introduction, Size, Age, and Growth; Fishes of Australia: Quick Facts; Australian Museum: Size Range; Naturalis: Size; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Short factsheet (updated 10/10/22); no region given for its maturity and litter figures; lists the order as 'Carcharhinidae'. Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG) Where FishBase: Length at first maturity / Size / Weight / Age; Florida Museum: introduction, Size, Age, and Growth; Fishes of Australia: Quick Facts; Australian Museum: Size Range; Naturalis: Size; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Undated digitised species key with transcription errors (e.g. 'over 80 rh'); older literature basis; its range limits (e.g. 'North Carolina to Brazil') were not used. Animal Diversity Web (University of Michigan Museum of Zoology) Where FishBase: Length at first maturity / Size / Weight / Age; Florida Museum: introduction, Size, Age, and Growth; Fishes of Australia: Quick Facts; Australian Museum: Size Range; Naturalis: Size; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
Body mass	Average mass is given as over 500 pounds (230 kg) or as 400 kg; the heaviest published weight is 449.5 kg, and the world-record fish, caught off Sarasota, Florida, weighed 991 pounds (450 kg).sources disagreeOff Australia, length at maturity corresponds to a weight of 113 pounds (51 kg) in males and 90 pounds (41 kg) in females.	Sources disagree · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.), Animal Diversity Web (University of Michigan Museum of Zoology) — how we know What each reading says averages over 500 pounds (230 kg) — Florida Museum of Natural History (University of Florida), average mass; Size, Age, and Growth world record 991 pounds (450 kg), caught off Sarasota, Florida — Florida Museum of Natural History (University of Florida), record fish; Size, Age, and Growth max. published weight 449.5 kg — FishBase (Froese & Pauly, eds.), maximum published weight range 350 to 500 kg; average 400 kg — Animal Diversity Web (University of Michigan Museum of Zoology), Physical Description data fields over 227 kg — Animal Diversity Web (University of Michigan Museum of Zoology), Physical Description text, alongside length up to approximately 6 m Typical mass differs: one account says the species averages over 500 pounds (230 kg), another gives an average of 400 kg with a range of 350 to 500 kg (its text says 'over 227 kg'), and that 500 kg exceeds the heaviest published figures (449.5 kg; 991 pounds or 450 kg). Florida Museum of Natural History (University of Florida) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Animal Diversity Web (University of Michigan Museum of Zoology) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Physical Description Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
Lifespan	Expected life span 20–30 years, or about 20 to 40 years by another account; maximum reported age 30 years. The oldest recorded individual was 44 years old, and another account says the species may live up to 44 years.sources disagreeAges are determined by counting vertebral rings. No captive lifespan is known.	Sources disagree · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.), Animal Diversity Web (University of Michigan Museum of Zoology), Museums Victoria (Fishes of Australia; Bray 2020) — how we know What each reading says expected life span 20–30 years — Florida Museum of Natural History (University of Florida), Size, Age, and Growth max. reported age 30 years — FishBase (Froese & Pauly, eds.), maximum reported age approximately 20 to 40 years; oldest recorded individual 44 years — Animal Diversity Web (University of Michigan Museum of Zoology), Lifespan/Longevity may live up to 44 years — Museums Victoria (Fishes of Australia; Bray 2020), Biology One database gives a maximum reported age of 30 years, whereas one account records an individual of 44 years and another says the species may live up to 44 years; expected life spans of 20–30 years and of about 20 to 40 years also differ. The account with the 44-year record also calls the longest known lifespan in the wild unknown. Florida Museum of Natural History (University of Florida) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Lifespan/Longevity; Fishes of Australia: Biology Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Lifespan/Longevity; Fishes of Australia: Biology Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Animal Diversity Web (University of Michigan Museum of Zoology) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Lifespan/Longevity; Fishes of Australia: Biology Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used. Museums Victoria (Fishes of Australia; Bray 2020) Where Florida Museum: Size, Age, and Growth; FishBase: Length at first maturity / Size / Weight / Age; ADW: Lifespan/Longevity; Fishes of Australia: Biology Checked by FaunaHub 2026-10-20 Limits Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note.
Social structure	Typically solitary, but has been noted migrating in groups during warmer periods, specifically summer. Mating system listed as polygynandrous (promiscuous).Only one account describes social behavior.	Matches source · Animal Diversity Web (University of Michigan Museum of Zoology) — how we know Animal Diversity Web (University of Michigan Museum of Zoology) Where ADW: Behavior; Reproduction (Mating System) Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
Reproduction	Viviparous; gestation about 11 months; pups born in spring or summer in the Northern Hemisphere, at 50–70 cm total length in most accounts; females breed once every two years. Litter size, placentation, birth size and female maturity length are reported differently.sources disagreeMaturity lengths of 2.25 m (males) and 2.10 m (females) are for waters off Australia. Ages at maturity of 15 years (females) and 6 years (males) are given by one account. The fetal sex ratio is about 1:1. One account gives birth size as approximately 65 cm.	Sources disagree · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.), Animal Diversity Web (University of Michigan Museum of Zoology), Australian Museum, Museums Victoria (Fishes of Australia; Bray 2020), Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG) — how we know What each reading says 6 to 42 pups per litter — Florida Museum of Natural History (University of Florida), Reproduction 6–42 pups per litter, every two years — Museums Victoria (Fishes of Australia; Bray 2020), Biology 13–42 young per litter (one reference) and 6–42 pups (another reference) — FishBase (Froese & Pauly, eds.), Life cycle and mating behavior 13 to 42 young — Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG), Habitat and Biology 6–33 pups per litter — Australian Museum, Reproduction 6 to 50 offspring (average 20–40) — Animal Diversity Web (University of Michigan Museum of Zoology), Reproduction data fields viviparous with a yolk-sac placenta — Florida Museum of Natural History (University of Florida), Reproduction aplacental viviparous — Museums Victoria (Fishes of Australia; Bray 2020), Biology size at birth 50 to 70 cm TL; also about 56 to 70 cm — FishBase (Froese & Pauly, eds.), two statements on the same page females mature at about 250 to 300 cm; males at about 234 to 269 cm — Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG), Size females mature at ~210–228 cm TL; males at ~255 cm TL — Australian Museum, Reproduction females mature at 210–300 cm TL; males at 225–269 cm TL — Museums Victoria (Fishes of Australia; Bray 2020), Biology off Australia, males mature at 2.25 m and females at 2.10 m total length — Florida Museum of Natural History (University of Florida), Size, Age, and Growth Litter size: 6–42 (Florida Museum, Fishes of Australia, FishBase), 13–42 (FishBase, Naturalis), 6–33 (Australian Museum), 6 to 50 (ADW). Placentation: yolk-sac placenta (Florida Museum, FishBase, Naturalis; ADW describes a placenta-like yolk-sac connection) versus aplacental (Fishes of Australia). Birth size: 50–70 cm versus about 56–70 cm (both in FishBase). Female length at maturity: about 250–300 cm (Naturalis) versus ~210–228 cm (Australian Museum). Florida Museum of Natural History (University of Florida) Where Florida Museum: Reproduction, Size, Age, and Growth; FishBase: Biology, Life cycle and mating behavior; ADW: Development, Reproduction; Australian Museum: Reproduction; Fishes of Australia: Biology; Naturalis: Habitat and Biology, Size Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: Reproduction, Size, Age, and Growth; FishBase: Biology, Life cycle and mating behavior; ADW: Development, Reproduction; Australian Museum: Reproduction; Fishes of Australia: Biology; Naturalis: Habitat and Biology, Size Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Animal Diversity Web (University of Michigan Museum of Zoology) Where Florida Museum: Reproduction, Size, Age, and Growth; FishBase: Biology, Life cycle and mating behavior; ADW: Development, Reproduction; Australian Museum: Reproduction; Fishes of Australia: Biology; Naturalis: Habitat and Biology, Size Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used. Australian Museum Where Florida Museum: Reproduction, Size, Age, and Growth; FishBase: Biology, Life cycle and mating behavior; ADW: Development, Reproduction; Australian Museum: Reproduction; Fishes of Australia: Biology; Naturalis: Habitat and Biology, Size Checked by FaunaHub 2026-10-20 Limits Short factsheet (updated 10/10/22); no region given for its maturity and litter figures; lists the order as 'Carcharhinidae'. Museums Victoria (Fishes of Australia; Bray 2020) Where Florida Museum: Reproduction, Size, Age, and Growth; FishBase: Biology, Life cycle and mating behavior; ADW: Development, Reproduction; Australian Museum: Reproduction; Fishes of Australia: Biology; Naturalis: Habitat and Biology, Size Checked by FaunaHub 2026-10-20 Limits Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note. Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG) Where Florida Museum: Reproduction, Size, Age, and Growth; FishBase: Biology, Life cycle and mating behavior; ADW: Development, Reproduction; Australian Museum: Reproduction; Fishes of Australia: Biology; Naturalis: Habitat and Biology, Size Checked by FaunaHub 2026-10-20 Limits Undated digitised species key with transcription errors (e.g. 'over 80 rh'); older literature basis; its range limits (e.g. 'North Carolina to Brazil') were not used.
Movement	Highly migratory and apparently nomadic; some populations move poleward to cooler water in summer, as off Florida and in the South China Sea, and individuals travel long distances each day.Classed as oceanodromous, and listed as a highly migratory species in Annex I of the 1982 Convention on the Law of the Sea.	Matches source · Florida Museum of Natural History (University of Florida), Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG), FishBase (Froese & Pauly, eds.), Animal Diversity Web (University of Michigan Museum of Zoology) — how we know Florida Museum of Natural History (University of Florida) Where Florida Museum: Habitat, Geographical Distribution; Naturalis: Habitat and Biology; FishBase: Environment, Distribution; ADW: Home Range Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). Naturalis Biodiversity Center (Sharks of the World, Linnaeus NG) Where Florida Museum: Habitat, Geographical Distribution; Naturalis: Habitat and Biology; FishBase: Environment, Distribution; ADW: Home Range Checked by FaunaHub 2026-10-20 Limits Undated digitised species key with transcription errors (e.g. 'over 80 rh'); older literature basis; its range limits (e.g. 'North Carolina to Brazil') were not used. FishBase (Froese & Pauly, eds.) Where Florida Museum: Habitat, Geographical Distribution; Naturalis: Habitat and Biology; FishBase: Environment, Distribution; ADW: Home Range Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's. Animal Diversity Web (University of Michigan Museum of Zoology) Where Florida Museum: Habitat, Geographical Distribution; Naturalis: Habitat and Biology; FishBase: Environment, Distribution; ADW: Home Range Checked by FaunaHub 2026-10-20 Limits Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
Human interaction	Fished commercially and recreationally; its large fins are highly valued in the Asian fin trade. Considered potentially dangerous to people, though few if any attacks can be definitely attributed to it because large hammerheads are hard to tell apart.	Matches source · Florida Museum of Natural History (University of Florida), FishBase (Froese & Pauly, eds.) — how we know Florida Museum of Natural History (University of Florida) Where Florida Museum: Importance to Humans; FishBase: Biology Checked by FaunaHub 2026-10-20 Limits Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia). FishBase (Froese & Pauly, eds.) Where Florida Museum: Importance to Humans; FishBase: Biology Checked by FaunaHub 2026-10-20 Limits Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's.

Not stated here, and why

Activity pattern— no source accepted yet: No accepted source states a daily or seasonal activity pattern (diurnal, nocturnal or crepuscular). Searched the Florida Museum, FishBase, ADW, Australian Museum, Fishes of Australia and Naturalis accounts and a 2025 Frontiers in Marine Science telemetry paper on great hammerheads off Andros, Bahamas (no diel terms). ADW only says the shark relies on its electrosensory system at dusk to detect prey and navigate. The NOAA species URL returned 404; Florida FWC and NSW DPI pages were blocked (403).

References for the facts above

UniversityFlorida Museum of Natural History (University of Florida)Supports: identification, range, habitat, diet, body-size, weight, lifespan, reproduction, movement; fisheries and fin trade. Retrieved 2026-10-20.Limitations: Discover Fishes profile revised 2018 (page last updated 05/29/2025); its conservation section is out of date; it describes the head notch both as 'shallow' and as 'prominent'; maturity figures are regional (off Australia).
ReferenceFishBase (Froese & Pauly, eds.)Supports: identification, range, habitat, diet, body-size, weight, lifespan, reproduction, movement; danger to people. Retrieved 2026-10-20.Limitations: Compiled summary citing many references; gives two litter-size ranges (13-42 and 6-42) and two birth sizes (50 to 70 cm TL and about 56 to 70 cm); its latitude bounds (40°N - 37°S) differ from the Florida Museum's and ADW's.
UniversityAnimal Diversity Web (University of Michigan Museum of Zoology)Supports: habitat, diet, body-size, weight, lifespan, social-structure, reproduction, movement. Retrieved 2026-10-20.Limitations: Student-written account (last updated 2023-08-08) with internal inconsistencies (mass range vs 'over 227 kg'; a 44-year record vs 'longest known lifespan in the wild ... unknown'); it calls skates and rays 'bony fishes' and the head 'scalloped' — those statements were not used.
UniversityAustralian MuseumSupports: habitat, body-size, reproduction. Retrieved 2026-10-20.Limitations: Short factsheet (updated 10/10/22); no region given for its maturity and litter figures; lists the order as 'Carcharhinidae'.
ReferenceMuseums Victoria (Fishes of Australia; Bray 2020)Supports: identification, range, diet, body-size, lifespan, reproduction. Retrieved 2026-10-20.Limitations: Australian focus; it alone calls reproduction aplacental; uses 'Giant Hammerhead' once in its fisheries note.
UniversityNaturalis Biodiversity Center (Sharks of the World, Linnaeus NG)Supports: body-size, reproduction, movement. Retrieved 2026-10-20.Limitations: Undated digitised species key with transcription errors (e.g. 'over 80 rh'); older literature basis; its range limits (e.g. 'North Carolina to Brazil') were not used.
ReferenceCalifornia Academy of Sciences (Eschmeyer's Catalog of Fishes)Supports: identity (accepted name, synonyms); range (distribution summary). Retrieved 2026-10-20.Limitations: Taxonomic catalogue (online version updated 21 Sep. 2026); distribution is a one-line summary.

Frequently Asked Questions — Great Hammerhead

How big do great hammerheads get?

The largest reported measured 610 cm in total length, but most are much smaller: a common length of 370 cm is given, and the species rarely exceeds 4.5 m. Females are typically slightly larger than males.

What do great hammerheads eat?

A wide range of prey, including bony fishes, other sharks, crabs, lobsters and squid, but they prefer stingrays and other batoids when available. One great hammerhead found off Florida had 96 stingray barbs lodged in its mouth.

Are great hammerheads dangerous to people?

The species is considered potentially dangerous, but few if any attacks can be definitely attributed to it, because the large hammerhead species are hard to tell apart.

How long do great hammerheads live?

Accounts differ: expected life spans of 20–30 years and of about 20 to 40 years are given. The oldest recorded individual was 44, and another account says the species may live up to 44 years, though one database gives a maximum reported age of 30.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.

UniversityFlorida Museum of Natural History (University of Florida) — Great hammerhead, Discover Fishes species profile — identification, range, habitat, diet, body-size, weight, lifespan, reproduction, movement; fisheries and fin trade
ReferenceFishBase (Froese & Pauly, eds.) — Sphyrna mokarran species summary — identification, range, habitat, diet, body-size, weight, lifespan, reproduction, movement; danger to people
UniversityAnimal Diversity Web (University of Michigan Museum of Zoology) — Sphyrna mokarran (great hammerhead) species account — habitat, diet, body-size, weight, lifespan, social-structure, reproduction, movement
UniversityAustralian Museum — Great hammerhead species account (Australia) — habitat, body-size, reproduction
ReferenceMuseums Victoria (Fishes of Australia; Bray 2020) — Sphyrna mokarran, Fishes of Australia — identification, range, diet, body-size, lifespan, reproduction
UniversityNaturalis Biodiversity Center (Sharks of the World, Linnaeus NG) — Sphyrna mokarran, Sharks of the World — body-size, reproduction, movement
ReferenceCalifornia Academy of Sciences (Eschmeyer's Catalog of Fishes) — Sphyrna mokarran, Eschmeyer's Catalog of Fishes — identity (accepted name, synonyms); range (distribution summary)