What do you think the future will hold for the otter? Short-term and long term?
Should Man go extinct, I believe they'll be able to replace us.
They can stand upright, have forward-facing eyes, and are able to use tools.
Some of them (smooth-coated, giant etc) live and hunt in groups where they're able to communicate and coordinate with each other.
Perhaps they'll go through the same kind of development that primates did when they became humans. Perhaps they'll develop better communication skills, maybe even a sort of language comparable to that of dolphins. Maybe they'll make more complicated tools, maybe even discover fire. I'd like to believe that could happen.
Of course, that's assuming we don't kill them all before that happens.