Weddell Seal

Fascinating facts about the Weddell Seal

• A Weddell seal can hold its breath for 80 minutes—long enough to watch a feature film—by collapsing its lungs, slowing its heartbeat to 15 beats per minute, and flooding its muscles with oxygen-storing proteins called myoglobin. When it surfaces, its heart rate spikes back to 120 beats per minute in seconds, a metabolic trick that lets it dive deeper than 600 metres without nitrogen narcosis killing it.
• Weddell seals carve breathing holes through Antarctic sea ice up to 2 metres thick using only their teeth—specially sharpened canines that wear down so fast they must re-file their holes every few days or risk suffocation. A single seal maintains 8 to 10 holes across its territory, each one a lifeline in an environment where the nearest open water might be 50 kilometres away.
• Mother Weddell seals give birth on ice in October, nurse their pups for just 6 weeks, then abandon them—but those pups double their weight in that time, gorging on milk so rich it's 50% fat (compare that to human breast milk at 4%). The pup must then teach itself to dive and hunt, alone, with no parental instruction, in one of Earth's harshest nurseries.
• A Weddell seal's whiskers are living sonar: each whisker vibrates independently to sense ripples in water as faint as a fish's tail flick 3 metres away, a sensitivity so acute they can hunt in total darkness under the Antarctic ice shelf. Their brain dedicates more neurons to processing whisker signals than humans devote to touch across our entire body.
• For over 50 years, Weddell seals have been the Antarctic's canary in the coal mine—in 1969, scientists began tagging them to study climate, and they've now become the longest-monitored mammal population south of the Antarctic Circle. Their breeding success and population trends reveal exactly how fast sea ice is vanishing; when the seals abandon their colonies early, the ice is thinning faster than predicted.

At a glance

About the Weddell Seal

In the icy vastness of Antarctica, the Weddell seal glides effortlessly through the frigid waters, its sleek, streamlined body undulating as it navigates the dark, mysterious depths. With each powerful stroke of its flippers, it propels itself forward, a master of this frozen realm, where it can dive to astonishing depths in search of prey. As it breaks through the surface, its large, dark eyes seem to hold a deep wisdom, a testament to its remarkable adaptability in one of the harshest environments on Earth.

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