Cats merely look for something small that moves so they can attack and kill it. Dolphins are genuinely curious and have a brain capable of more than the mere reflex actions (Feed! Fight! Flee! F**k! - repeat ad nauseam and that is feline existence.
Yes, curiosity being a sign of intelligence. I suppose there’s a researcher out there who can come up with a sonar sound to keep them away from oil rigs. Who knows?