It was kind of a dick move to create animals that require air, then confine them to the freaking ocean
If you are talking about dolphins they used to be wolf like creatures that due to scarcity of food they had to hunt in water so they slowly evolved into water mammals, dolphins still have claw bones but they are unnecessary and dolphins will get rid of them with time and will develop abilities to breath under water
(This also partially applies to whales)
They were what now?
Mother Nature, come out here I just want to talk
While that reconstruction is horribly shrinkwrapped, I think it’s Ambulocetus which looked more like this
This was the whale ancestor that was just beginning to make its life in water functioning pretty much like partially marine mammals do (read: they’re basically otters) so honestly, OP made it sound much worse than reality.
Now Pakicetus is the real wolf-like whale ancestor, he looks like this:
And he’s just some big dude trying to make his way in the Indian-Subcontinent.
ALSO, OP will have you believe that Dolphins will lose their “claw bones” and breathe underwater one day which is transcendently wrong one multiple levels.
My guess is by “claw bone” OP means fin bones that evolved from claw bones, (which are not useless like they said), and this is what they look like now.
It looks like a claw because it used to be claw (on Pakicetus) nothing crazy, and now it’s used for fin movement. Evolution does that to things.
Furthermore, evolution is not on some predictable guided projectory. No one can say for certain what future cetaceans (dolphins, whales) will look like. They may evolve to breathe underwater, they may evolve to walk back on land. They may lose their fin bones, but probably not because they’re used as support for the fins.
And one final nitpick, I have no idea what OP means by “This also partially applies to whales.” If they’re talking about evolutionary history, all cetaceans share the same common ancestor so whales and dolphins shared great great(x10,000,000) grand daddies
If they’re talking about the “claw” whales also have fins supported by very similar bones as dolphins, because again, they evolved from the same animal
TL;DR: Whales and Dolphins shared an ancestor who was a cute otter-looking fellow. Cetaceans don’t have claws, they have fully functioning fin bones evolved from claws and OP making a definite statement about how Cetaceans will evolve is sheer hubris at best.
Cadet-For-Your-SpaceRescue 