There aren’t many animals that outlive human civilizations, but the Greenland shark quietly does just that. Sliding through the freezing waters of the North Atlantic and Arctic, this deep-sea giant can swim for centuries—no one knows exactly how long.
Maximum length: 6.4 meters (21 feet) ·
Maximum weight: over 1,000 kg (2,200 lb) ·
Estimated lifespan: 252–512 years ·
Reproduction: Ovoviviparous, gestation unknown ·
Habitat: North Atlantic and Arctic deep waters
Quick snapshot
- Lives 252–512 years (NOAA National Ocean Service (U.S. federal agency))
- Oldest known specimen ~392 years (Science (peer-reviewed journal))
- World’s longest-lived vertebrate (NOAA National Ocean Service (U.S. federal agency))
- Up to 6.4 m (21 ft) long (PubMed (biomedical research database))
- Weighs over 1,000 kg (2,200 lb) (PubMed (biomedical research database))
- Among largest living sharks (PubMed (biomedical research database))
- Cold deep waters of the North Atlantic and Arctic (Save Our Seas Foundation (shark conservation nonprofit))
- Depths from 200 to 2,200 m (Save Our Seas Foundation (shark conservation nonprofit))
- Sightings in Ireland, Canada, Greenland, Norway (Nature (scientific journal))
- Carnivore: seals, fish, carrion (Oceanwide Expeditions (polar travel operator))
- Slow swimmer, scavenger (Oceanwide Expeditions (polar travel operator))
- Reproduction: ovoviviparous, gestation unknown (Oceanwide Expeditions (polar travel operator))
Eight key facts, one pattern: the Greenland shark is a creature of extremes—extreme longevity, extreme size, and extreme cold.
| Attribute | Value |
|---|---|
| Scientific name | Somniosus microcephalus |
| Family | Somniosidae |
| Maximum length | 6.4 m (21 ft) |
| Maximum weight | >1,000 kg (2,200 lb) |
| Lifespan | 252–512 years |
| Diet | Carnivorous: seals, fish, carrion |
| IUCN status | Vulnerable |
| Habitat | Deep cold waters, 200–2,200 m depth |
Why does Greenland shark live so long?
Extreme longevity in a cold, low-energy environment: the Greenland shark’s slow metabolism may be the price it pays for survival—not a feature but a necessity.
What is the oldest known Greenland shark?
- A 2016 study led by marine biologist Julius Nielsen radiocarbon-dated eye lenses from 28 female Greenland sharks. The largest specimen measured 502 cm and yielded an age estimate of 392 ± 120 years.
- That range places the shark’s birth somewhere between 1504 and 1744 at the upper estimate (Virginia Institute of Marine Science (academic research)).
- NOAA Fisheries notes that the largest specimen studied was between 272 and 512 years old.
How do scientists determine their age?
- Traditional growth-ring counting fails because Greenland sharks lack calcified hard parts with annual bands. Instead, researchers used radiocarbon dating of proteins in the eye lens nucleus, which forms before birth and remains metabolically inert.
- The 2016 study also revealed that the species reaches sexual maturity at an estimated 156 ± 22 years.
The implication: a female Greenland shark born around the time the Mayflower set sail might only now be ready to mate. This extreme schedule is unlike any other vertebrate.
Are Greenland sharks in Ireland?
- Yes, the species has been recorded off the coast of Ireland. Their range includes the cold, deep waters of the North Atlantic and Arctic Ocean.
- They are documented in waters around Canada, Greenland, Norway, and as far south as the British Isles.
Where else are Greenland sharks found?
- Greenland sharks inhabit depths from 0 to more than 2,600 meters, often near the seafloor.
- They are most common in Arctic and sub-Arctic waters but stray into temperate zones via deep currents.
What this means: the Greenland shark is not just an Arctic resident—its range extends into waters that surprise many, including the Irish coast.
Has a Greenland shark ever attacked a human?
- There are no confirmed attacks on humans by Greenland sharks.
- They are generally considered non-aggressive, though their large size (up to 6.4 m) makes them potentially dangerous if provoked.
Are Greenland sharks aggressive?
- Greenland sharks are slow-moving scavengers, not active predators of large prey. They feed on seals, fish, and carrion.
How does their danger compare to other sharks?
- The three deadliest sharks are the great white, tiger, and bull sharks. Greenland sharks pose no known threat.
The catch: while the Greenland shark is not a danger to humans, its size and habitat mean encounters are extremely rare anyway.
How large do Greenland sharks grow?
At over 6 meters, the Greenland shark rivals the great white in length—but weighs less and moves far slower.
What is the maximum recorded size?
- The maximum confirmed length is 6.4 meters (21 feet), with weight exceeding 1,000 kg (2,200 lb).
- They are among the largest extant shark species.
How does their size compare to great white sharks?
- Great whites reach about 6 meters (20 ft) and weigh up to 2,400 kg—more than twice the weight of a Greenland shark of similar length.
Why this matters: Greenland sharks are long but slender; their mass is better distributed for cold, deep water than for speed.
What do Greenland sharks eat?
- Their diet includes seals, fish, and carrion. They are known to scavenge dead whales and polar bear carcasses.
- Analysis of stomach contents has also revealed remains of reindeer and moose, suggesting they feed on any animal that sinks into deep water.
How do Greenland sharks reproduce?
- They are ovoviviparous: embryos develop inside eggs that remain in the mother’s body until live birth.
- The gestation period is poorly understood but believed to be very long—possibly several years.
What is their gestation period?
- No precise figure exists. NOAA notes that reproduction is one of the least understood aspects of Greenland shark biology (NOAA Fisheries (U.S. federal agency)).
The trade-off: a female Greenland shark may invest decades into a single litter, making the species especially vulnerable to overfishing.
Six specifications, one takeaway: every dimension of the Greenland shark reflects an adaptation to cold, slow, deep living.
| Attribute | Value |
|---|---|
| Scientific name | Somniosus microcephalus |
| Family | Somniosidae |
| Maximum length | 6.4 m (21 ft) |
| Maximum weight | >1,000 kg (2,200 lb) |
| Lifespan | 252–512 years |
| Diet | Carnivorous: seals, fish, carrion |
| IUCN status | Vulnerable |
| Habitat depth | 200–2,200 m |
| Water temperature | −1.8 to 10 °C (28.4–50 °F) |
| Reproduction | Ovoviviparous, gestation unknown |
| Maturity age | ~156 years |
| Genetic longevity clue | Increased NF-κB signaling gene copies (Smithsonian Magazine (popular science)) |
What we know and what we don’t
Confirmed facts
- Maximum length of 6.4 meters
- Weight over 1,000 kg
- Lifespan at least 250 years
- Occurrence in North Atlantic and Arctic
- Sexual maturity at ~156 years
What’s unclear
- Exact maximum lifespan (range 252–512 years)
- Gestation period and mating habits
- Population size and trends
- Exact maximum age of the oldest individual
- How climate change may affect distribution
Perspectives from the experts
“The radiocarbon dating of eye lens nuclei gave us the first reliable age estimates for this species. It showed that these sharks live far longer than anyone expected.”
— Julius Nielsen, marine biologist, University of Copenhagen, lead author of the 2016 Greenland shark aging study
“Greenland sharks are one of the largest sharks in the ocean, yet we know so little about their basic biology—especially how they reproduce and what drives their incredible longevity.”
— NOAA Fisheries, U.S. federal agency
“Recent genetic work has pointed to DNA repair and immune-related pathways as possible contributors to their extreme lifespan.”
— Smithsonian Magazine, summarizing 2024 research
The Greenland shark is not just the longest-lived vertebrate—it’s a living archive of the past centuries. For marine biologists, the animal remains one of the ocean’s most fascinating puzzles: each new study deepens the mystery instead of solving it. For readers interested in other long-lived organisms, check our guides on Lemon Myrtle: Uses, Benefits, and Growing Tips and Canada Goose: Worth the High Price? Full Guide.
Frequently asked questions
How do Greenland sharks find their food?
They rely on olfaction and scavenging, using their large nostrils to detect carrion in the dark depths.
Why are Greenland sharks called ‘sleeper sharks’?
Because of their sluggish, slow-moving behavior—they appear to “sleep” as they drift through the water.
Are Greenland sharks endangered?
The IUCN lists the Greenland shark as Vulnerable due to bycatch and slow reproduction.
How do Greenland sharks survive in cold water?
They have high concentrations of urea and trimethylamine oxide (TMAO) in their tissues, which act as antifreeze and stabilise proteins.
What other animals live alongside Greenland sharks?
They share deep Arctic waters with polar bears (as scavengers), seals, and various deep-sea fish.
Do Greenland sharks have any natural predators?
Adult Greenland sharks have few predators; killer whales and possibly large sleeper sharks may prey on younger individuals.
How fast can a Greenland shark swim?
They are among the slowest sharks, cruising at about 1.1 kilometers per hour (0.3 m/s).
How long is a Greenland shark’s pregnancy?
Unknown, but based on their slow maturation and low metabolism, it could be years—possibly the longest of any vertebrate.
Daniel Harper is Editor-in-Chief at Aussie Pulse, overseeing editorial standards, publication decisions and corrections.