Seal Facts & Trivia: Whiskers, Dives and Misnamed Diets

• Northern elephant seals average just 2 hours of sleep a day during months-long foraging trips at sea — among the least sleep of any mammal.
• A diving harbor seal drops its heart rate from 75–120 beats per minute to just 4–6 beats per minute.
• Each seal whisker carries roughly 1,500 nerve endings — about 7.5 times more than a cat's whisker, which has around 200.
• Weddell seals stay under for up to 45 minutes and reach 720 m, and they are the southernmost mammal that lives on the Antarctic continent year-round.
• Weddell seals grind their own teeth down to the pulp cavity sawing breathing holes in sea ice; the resulting infections are a documented cause of adult death, rising sharply after age 8–9.
• Southern elephant seal bulls reach 3,000 kg, and the species has been recorded diving 2 km down and holding its breath for 2 hours. The headline '2 km deep, 2 hours' figures are extreme records, not routine behaviour. The same source says most dives are about 30 minutes at 300–800 m. And it is only the southern elephant seal that hits 3,000 kg — a harbor seal tops out near 285 pounds.
• Every northern elephant seal alive today — over 170,000 animals — descends from a surviving group of roughly 20 to 100 individuals after 19th-century hunting left the species presumed extinct.
• The famous fluffy white 'whitecoat' of a harp seal pup is a temporary coat called lanugo that is shed by 3 to 4 weeks of age.
• The Baikal seal of Siberia is the only seal whose entire population lives in fresh water, and it can live more than 50 years.
• About 1,600 Hawaiian monk seals remain — roughly 1,200 in Papahānaumokuākea and 400 in the main Hawaiian Islands — making it one of the most endangered seals on Earth.
• Wild grey seals clap their fore-flippers underwater to produce a gunshot-like crack; the behaviour was first published in Marine Mammal Science in February 2020, after a diver spent 17 years trying to film it.
• Puijila darwini, a roughly 20–24 million-year-old fossil from Devon Island in Arctic Canada, shows what seal ancestors looked like before flippers: four walking legs with webbed toes.

“The barking animal balancing a ball on its nose at the aquarium is a seal.” That is a sea lion — an eared seal. True seals have no external ear flaps, cannot rotate their hind flippers to walk, and are markedly quieter, communicating with grunts rather than barks. The circus 'seal' act is almost always an otariid.

“Crabeater seals eat crabs.” They eat almost nothing but Antarctic krill, straining it through multi-lobed teeth. The name comes from a German word for crustaceans generally, not crabs. There are no crabs in their Antarctic range to speak of.

“A seal pup alone on a beach has been abandoned and needs rescuing.” Mothers routinely leave pups ashore for a day or two while they forage. Crowding or picking up the pup is what actually causes abandonment, because the mother will not come ashore to a beach full of people. Stay 100 yards back.

“Seals cry real tears when they are frightened or sad.” Seals have no tear ducts to drain fluid into the nose, so the thick tears that lubricate their eyes on land simply spill down the face. The 'weeping' look is plumbing, not emotion.

“Leopard seals are penguin specialists that live on penguin meat.” Stable-isotope work on the Antarctic Peninsula found spring diets dominated by krill and fish, with penguins roughly a quarter of intake. Individual seals specialise — big females do hunt penguins and fur seal pups — but the species as a whole is closer to a krill-eater than a penguin hunter.

Seals carry Irish and Scottish selkie folklore into modern animation. John Sayles filmed The Secret of Roan Inish in 1994, and Tomm Moore's Cartoon Saloon released Song of the Sea in 2014, in which a girl called Saoirse turns out to be the last seal-child; it earned an Academy Award nomination for Best Animated Feature. Also in 1994, Paramount released Andre (19 August 1994), a family film with Tina Majorino based on the real Rockport, Maine harbour seal — with the twist that the title seal was played by a California sea lion named Tory. George Miller's Happy Feet (17 November 2006) gave a generation of children their leopard-seal nightmare in an underwater chase scene that ends with Mumble losing tail feathers. On the internet, the seal emoji 🦭 (U+1F9AD) arrived with Unicode 13.0 in 2020, and Neil the Seal, a southern elephant seal in Tasmania, became a TikTok phenomenon covered by NPR in December 2023 for flattening fences and blocking roads.

Hoover, a harbour seal orphaned at Bethel Point, Maine in 1971 and raised by George Swallow, learned to imitate human speech in a broad Maine accent at Boston's New England Aquarium, saying "hello there" and "come over here"; he died in 1985 and remains the best-documented case of vocal learning in a seal. Andre, born May 1961 in Penobscot Bay and adopted by Rockport harbourmaster Harry Goodridge, wintered at the New England Aquarium and swam home to Rockport each spring until his death on 19 July 1986; his stone likeness still stands at the harbour. Rocky (RH58) delivered the first Hawaiian monk seal pup ever recorded on Waikīkī Beach on 29 June 2017 — the pup was named Kaimana. Freddie Mercury, a Thames seal near Hammersmith Bridge, was euthanised in March 2021 after a dog attack.