Heavy weights with unexpected skills - The grazing grounds of the walrus This heavy weight is known for its characteristic, massive teeth that stick out of the upper jaw. They are horrible weapons. Another distinct feature is their weight: males can weigh up to 1500 kilos. A large part of this body mass is a thick layer of fat underneath leathery skin - and it is needed because these large seals live in the polar sea on the edge of the pack ice. Without their teeth the animals could not survive - they are used as tools for many things. For one thing the teeth are used as ice picks to pull their giant bodies back onto the ice, then they also use their teeth to rummage through the mud on the ocean floor to search for snails, crabs and clams. Except for us humans they should not have many predators. But there is one other and it is primarily going for their young - the polar bear. It is very difficult to observe walruses: the arctic climate is the first deterrent. The Australian walrus specialist Jason Roberts has been living in Spitzbergen for many years and has been studying walruses and their family hierarchy up close. He takes us on an expedition to the 80th latitude where we will observe walruses as they feed underwater as it has never been filmed before. We will follow those heavy weights under the ice and will be confronted with one of the rarest sharks - the Greenland shark.