Weddell seals, which inhabit the ice fields and ice edges of the Southern Ocean, are master punchers and valuable assistants to oceanographers.
The Weddell Seal: Experts in Drilling
Weddell seals need to surface frequently to breathe, with intervals of 10-20 minutes, sometimes up to 70 minutes. When there is no ice, surfacing to breathe is easy; however, when the sea freezes over, breathing becomes a major problem. When a Weddell seal is trapped under sea ice or ice floes, it cannot surface to breathe at will. When it becomes unbearably suffocated, it will desperately gnaw at the ice. After exhausting all its strength, it will carve a hole, allowing it to crawl out and weakly breathe. However, its mouth will be worn raw, bleeding profusely, staining the inside and outside of the ice hole; its teeth will be worn down, flattened, or even lost, rendering it unable to eat or fight its predators. For this reason, Weddell seals, which could live for over 20 years, generally only live 8-10 years, and some even die after only 4-5 years. Even more seriously, some Weddell seals died from lack of oxygen and exhaustion before they even emerged from their burrows.
To preserve the ice caves they've carved out with their blood and lives, Weddell seals periodically re-gnaw on them to prevent the entrances from freezing again. In this way, the ice caves become their gateways to the ocean, allowing them to breathe and move about.
The ice caves carved out by Weddell seals with their blood and lives are invaluable sites for oceanographers conducting marine scientific research. Oceanographers can use these ice caves to collect seawater samples for marine chemistry and biology research; they can also place various oceanographic instruments inside for studies in marine physics and other disciplines. Drilling such an ice cave manually would require a tremendous amount of manpower and resources. Therefore, Weddell seals are known as master drillers and invaluable assistants to oceanographers.
