Compared to other animals, what superlative applies to the sea otter's coat density?

Answer

Densest in the animal kingdom

Sea otters possess the densest fur in the animal kingdom, estimated to range between 600,000 to 1,000,000 hair follicles per square inch, which traps vital insulating air.

Compared to other animals, what superlative applies to the sea otter's coat density?
locationanimalwildlifesea otter