He defends his claim and relocates his harem. But one challenger won't give up so easily. They can crash at nearly 100 km/h. Eventually, a final blow signals the end.

 

When spring comes to Siberia, the floodgates open. Over millennia, racing waters have cut swathes through hard rocks and pine forests. In Southeast Siberia, much of it runs to the seventh largest fresh water lake in the world, 636 kilometers long and 80 kilometers at its widest, this is Lake Baikal. This record- breaking lake holds 20% of the earth's fresh water as much as all five of America's great lakes combined. 

 

But with the water temperature rarely rising above eight degrees Celsius, it is not as inviting as it looks. But that's ok for the residents--the only fresh water seals in the world, the Baikal seals.

 

No one knows how they got to the enclosed lake. One theory is that they evolved from ringed seals half a million years ago when the Arctic Ocean extended further into Siberia.