The Arctic fox is one that could dominate in cross-country skiing because
the fur on their feet gives them traction and that traction allows them to run
fast (probably faster than a human skier).The Arctic hare is another one
that would dominate in the ski jump because it can run on snow as fast as
40 mph and that speed would help it go far in the air. A seal could do good
in the skeleton because seals slide on their stomachs all the time and they
could probably go faster than any person while sliding.