While exploring Antarctica in the 1820s, the British Captain James Weddell came across a large seal. Suspecting it differed to other Antarctic breeds he killed several and sent them to an Edinburgh museum for analysis. Confirmation (see below for an explanation of why Weddell seals are different) resulted in these fascinating marine mammals being named Weddell seals.
When winter arrives, Antarctic mammals head north to warmer climes. But the Weddell seal remains. They stay warm by living below the ice, although they must ensure air holes in the ice remain open to ensure survival. Frequent gnawing at these ice holes causes tooth erosion and is thought to be the reason the Weddell does not live as long as other seals.
The Weddell seal feeds mainly on squid and fish. They have been seen blowing air bubbles into cracks under the sea ice to flush out prey. Common perception is that these creatures are docile and friendly, but scientists from the University of California have caught on camera Weddell seals stalking and wrestling to death a metre-long fish.
The Weddell seal is a consummate diver, reaching depths of up to 700 metres while holding its breath for well over an hour. This amazing ability is thought to be due to a high concentration of a protein called myoglobin which the Weddell seals stores in their muscles.
Seals on Film
"Springtime for the Weddell Seals", made by Luc Jacquet, the award winning director of the documentary, "March of the Penguins", follows a mother and her newborn pup over the first few months of its life.
During the mating season, male Weddell seals have been observed "hanging around" ice holes defending the territory from other males in the hope of seducing the female as she comes up for air.
Mating takes place underwater but the pups are born between September and November in colonies above the ice. Females only give birth after reaching about six years of age and to just one pup annually.
Weddell pups stay with their mothers for longer than others of their species; weighing an average of 27 kilograms (60 pounds) at birth, they can gain as much as 90 kilograms (200 pounds) in the six to eight weeks of feeding on their mothers’ rich fatty milk.
Killer whales and leopard seals are the main predators but due to the Weddell living so far south and often under several metres of ice, they are relatively safe. Scientists have found brucella antibodies in a Weddell seal. Brucellosis can cause sterility and spontaneous abortion in cattle but so far there is no evidence of the disease itself present in the Antarctic.