Last week, Dunedin was visited by a juvenile male Weddell Seal. What a treat to see, and nearly as cute as our locals New Zealand sea lions/pakake!
Biology: Weddell seals are true seals. Their bodies are long and rounded, their fur is mottled grey/brown, they have short fore-flippers, relatively small heads and internal ears. They are the most southerly breeding seal and breed on fast ice (sea ice attached or stuck to the coast) along the Antarctic coastline during austral spring. Males are 2.9 m and can weigh up to 450 kg and females are 3.3 m and can weigh over 500 kg. Female’s have a gestation period of eleven months, including delayed implantation of two months and their newborns are 1.5 m and about 29 kg. They typically have one pup, but can have twins – being the only seal species to do so.
They are generalist predators and are the only predator, along with the Emperor penguin (Aptenodytes forsteri), to inhabit fast ice all year. They can dive to depths of over 600 m, and remain submerged for at least 82 minutes. Large oxygen stores in their blood and muscle enable their exceptional breath-holding ability. They have unique vocalisations, which have been described as high-pitched pings and boings and like ‘sci-fi spaceships’. They have a life expectancy of about 30 years.
Conservation status: ‘Least Concern’ on the IUCN Red List of Threatened Species.
Threats: Climate change; food availability; human interference – until the 1990’s they were a food source for humans and dogs; and predation by orca and leopard seals.
Photo: Sian Mair.