The problem is that bears can swim. To enclose 1000Km of open sea in a "storm-proof, crushing-iceberg proof, bear-proof" barrier to keep penguins out and bears

The problem is that bears can swim. To enclose 1000Km of open sea in a "storm-proof, crushing-iceberg proof, bear-proof" barrier to keep penguins out and bears in would be... a defiant task. If we put polar bears in Antarctica, sooner or later we'll have polar bears roaming in Argentina.