Seal

1. The Deep Diving Champions

Seals are some of the most impressive divers in the animal kingdom. Elephant seals can dive to depths of 2,400 meters (7,800 feet) and stay submerged for up to 100 minutes. They achieve this by having more blood (and thus more oxygen storage) than other mammals, and they can reduce their heart rate by 50–80% during dives to conserve oxygen.

2. The "Bottling" Sleep

Seals can sleep in water using a technique called "bottling"—they float vertically with only their nose above the surface, allowing them to breathe while resting. They can also sleep on the bottom, holding their breath for extended periods. This ability to sleep underwater is unique among marine mammals.

3. The Whisker Radar

A seal's whiskers (vibrissae) are incredibly sensitive. They can detect the water movements created by fish swimming up to 100 meters away. The whiskers work like underwater radar, allowing seals to hunt in complete darkness or murky water by "feeling" the wake left by prey.

4. The Belly Crawl

Unlike sea lions (which can walk on all fours), seals have hind flippers that cannot rotate forward. On land, they move by wriggling on their bellies—a movement that looks awkward but is surprisingly efficient. This is why they prefer to stay in the water, where they're graceful and fast.

5. The Blubber Blanket

Seals have a thick layer of blubber (fat) that serves multiple purposes: insulation in cold water, energy storage for long migrations, and buoyancy control. Some seals can have blubber that makes up 50% of their body weight, allowing them to survive in freezing polar waters.

6. The Milk Factory

Seal milk is incredibly rich—it can be 50% fat (compared to human milk at 4% fat). This allows seal pups to grow rapidly. A harbor seal pup can gain 2–3 kg per day while nursing. The mother fasts during this period, living off her blubber reserves.

7. The Molt Marathon

Once a year, seals undergo a complete molt—they shed all their fur and grow a new coat. During this time, they spend more time on land (or ice) and are less active. The new fur is waterproof and provides better insulation. This is a vulnerable time for seals, as they're less agile and more exposed to predators.

8. The Playful Personality

Seals are known for their curiosity and playfulness. They often approach divers, sometimes nibbling on fins or cameras, or playing with bubbles. This behavior is especially common in younger seals. They seem to enjoy interaction and will sometimes follow divers for extended periods.

9. The Size Spectrum

Seals range from the tiny Galapagos Fur Seal (about 1 meter, 30 kg) to the massive Southern Elephant Seal (up to 4 meters, 2,000+ kg—the size of a small car). The elephant seal gets its name from the inflatable, trunk-like nose of adult males, used for making loud roaring sounds during mating season.

10. The Ice Dwellers

Many seal species are perfectly adapted to life on and under ice. They can maintain breathing holes in ice that's meters thick, using their teeth and claws to keep them open. Some species, like Weddell seals, can dive under ice for over an hour, navigating through underwater ice caves and crevices.