Its closest relatives are other cowsharks in the family Hexanchidae, such as the Sixgill Shark (Hexanchus griseus) and Bluntnose Sixgill Shark (Hexanchus nasutus).
8 to 10 ft (2.5 to 3 m)
Length
200 to 300 lbs (90 to 136 kg)
Weight
About
The Seven Gill Shark (Notorynchus cepedianus), also known as the Broadnose Sevengill Shark, is a large coastal predator in the family Hexanchidae. Unlike most sharks, which have five gill slits, this species is easily recognized by its seven pairs of gills, a primitive trait linking it to some of the ocean’s earliest shark lineages.
Seven Gill Sharks are found worldwide in temperate waters, including the coasts of South Africa, South America, Australia, New Zealand, Japan, and the western United States. They prefer shallow bays, estuaries, and kelp forests but also range into deeper offshore waters.
Adults average 7–10 feet (2.1–3 meters) in length and weigh 200–240 pounds (90–110 kg), with females generally larger than males. They have broad, blunt snouts, small eyes, and mottled gray to brown bodies often marked with black spots. Their single dorsal fin, located far back near the tail, adds to their distinctive silhouette.
As opportunistic hunters, Seven Gill Sharks feed on a wide range of prey, including fish, rays, other sharks, seals, and carrion. They often hunt cooperatively in packs, a rare behavior among sharks, enabling them to overpower large animals. Their strong, saw-like teeth in the lower jaw are well adapted for tearing into tough prey.
Reproduction is ovoviviparous: embryos develop inside the female, nourished by yolk sacs, and are born live. Litters can be exceptionally large, ranging from 80 to over 100 pups, though many do not survive to adulthood.
Though generally not aggressive toward humans, Seven Gill Sharks can be bold if provoked or when food is present. They face threats from overfishing, bycatch, and habitat loss, and populations are considered Vulnerable in some regions.
With their ancient lineage, unusual gill count, and cooperative hunting, the Seven Gill Shark is one of the most fascinating and distinctive coastal sharks.
Threatened:
Extinct
Critically Endangered
Endangered
Vulnerable
Near Threatened
Least Concern
Physical Characteristics
The Seven Gill Shark is a large, primitive shark distinguished by having seven gill slits instead of the usual five.
Body Shape:
Heavy-bodied with a broad, blunt snout and wide head.
Skin & Coloration:
Grey to brown with black spots or blotches along the body. Underside is lighter, providing countershading camouflage.
Head & Eyes:
Broad, rounded snout with small eyes and strong jaws. Seven gill slits extend nearly down the throat—an ancient trait among sharks.
Mouth & Teeth:
Lower jaw lined with large, comb-shaped saw-like teeth, while the upper jaw has smaller, pointed teeth.
Fins:
Single dorsal fin located far back near the tail. Pectoral fins are broad and rounded, aiding in maneuverability.
Tail:
Long, powerful tail with an extended upper lobe adapted for bursts of speed when attacking prey.
Size:
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Length: Typically 8 to 10 ft (2.5 to 3 m), maximum recorded ~9.8 ft (3 m).
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Weight: Commonly 200 to 240 lbs (90 to 110 kg), with some exceeding 300 lbs (136 kg).
The Seven Gill Shark’s extra gill slits, heavy build, and distinctive teeth make it one of the most recognizable and ancient-looking sharks in today’s oceans.
Reproduction
Seven Gill Sharks are ovoviviparous, giving birth to live young that develop inside the mother’s body without a placental connection.
Mating Season:
Breeding occurs in spring and early summer in shallow coastal waters. Courtship often involves males biting females for grip during copulation.
Gestation:
Pregnancy lasts about 12 months, though some evidence suggests variation depending on water temperature.
Birth:
Litters are very large compared to most sharks, ranging from 60 to over 100 pups.
Pups:
Newborns measure about 16 to 18 in (40–45 cm) at birth and are fully independent from the moment they are born.
Maturity:
Males reach maturity at 4.5 to 5.5 ft (1.4–1.7 m), while females mature later, at 6.5 to 7.5 ft (2–2.3 m).
Reproductive Strategy:
High fecundity (large litters) offsets high juvenile mortality, ensuring survival of the species in unpredictable coastal and estuarine environments.
Lifespan
Seven Gill Sharks are long-lived coastal predators with slow maturity typical of larger sharks.
Average Lifespan in the Wild:
They live around 30 to 50 years, depending on environmental conditions and fishing pressures.
Lifespan in Captivity:
Rarely kept in captivity due to their size and active swimming needs; survival is usually shorter than in the wild.
Life Cycle Dynamics:
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Pups: Born at 16–18 in (40–45 cm), immediately independent hunters.
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Juveniles: Grow steadily in shallow nurseries, vulnerable to larger predators.
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Adulthood: Males mature at 4.5–5.5 ft (1.4–1.7 m), females later at 6.5–7.5 ft (2–2.3 m).
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Senior Age: Remain reproductively active well into older age, though fertility gradually declines.
Threats to Longevity:
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Overfishing: Caught for meat, leather, and oil.
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Bycatch: Frequently taken in gillnets and longlines.
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Habitat Loss: Nursery areas in estuaries and coastal zones are especially vulnerable to degradation.
The Seven Gill Shark’s extended lifespan and slow maturity make it particularly vulnerable to overexploitation, despite its high reproductive output.
Eating Habits
Seven Gill Sharks are powerful, opportunistic predators that feed on a wide variety of marine animals.
Diet:
They consume bony fish, rays, other sharks, seals, sea lions, carrion, and occasionally seabirds. Their broad diet makes them apex predators in coastal ecosystems.
Hunting Strategy:
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Ambush Predators: Use camouflage in kelp beds and rocky reefs to surprise prey.
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Pack Hunters: Unusually for sharks, they sometimes hunt cooperatively in groups to overwhelm large prey like seals.
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Opportunistic Feeders: Readily scavenge carcasses of whales, seals, and large fish.
Feeding Method:
Their saw-like lower teeth slice through flesh while smaller upper teeth grip prey. They can twist and thrash to tear apart large animals.
Group Feeding:
While often solitary, they may aggregate in groups when prey is abundant, particularly around seal colonies.
Ecological Role:
As apex predators, they regulate populations of fish, marine mammals, and other sharks, maintaining balance in temperate marine ecosystems.
Uniqueness
The Seven Gill Shark is one of the most primitive and distinctive modern sharks, with features that set it apart from most others.
Seven Gill Slits:
Most sharks have five gill slits, but this species has seven, a trait linked to ancient shark lineages.
Ancient Lineage:
They belong to the cowshark family (Hexanchidae), which dates back over 200 million years, making them living relics of prehistoric seas.
Unique Teeth:
They possess two different tooth types—comb-shaped teeth in the lower jaw and pointed teeth in the upper—specialized for gripping and slicing.
Pack Hunting:
Unusual among sharks, they sometimes hunt cooperatively in groups to bring down larger prey such as seals.
Habitat Versatility:
They thrive in coastal areas, kelp forests, estuaries, and rocky reefs, showing remarkable adaptability to varied marine environments.
Cultural Significance:
Feared and respected in folklore, they have a long history in human interactions with coastal communities.
The Seven Gill Shark’s extra gills, ancient lineage, and rare pack-hunting behavior make it one of the most unique sharks alive today.
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FAQ’s
1. What is the closest species to the Seven Gill Shark?
2. How does the Seven Gill Shark compare to other sharks?
Unlike most sharks with five gill slits, they have seven. They are more primitive in design, can hunt in packs, and are bulkier coastal predators.
3. What national parks provide the best opportunities to see a Seven Gill Shark?
They can be seen in Table Mountain National Park Marine Protected Area (South Africa), Point Reyes National Seashore (USA), and Galápagos Marine Reserve (Ecuador).
