Why do wild Orca's have a straight dorsal fin while those in captivity seem to have a curved, sagging one?

Answer 1

When push comes to shove they have yet to figure EXACTLY what causes that. Some will argue it is diet/health, others water quality, some will say it is due to depression while others aruge it is the room they have to swim/live. Then again there are people who say it is a little of all of those.

So, it really depends on who you talk to.

Personally I do not believe it has anything to do with diet, health (physical not mental) or water quality. For the most part the health care and food that captive animals get is outstanding. As far as water quality that is in the same boat as diet and health care. Granted in those crappy road-side zoos and zoos that are in poor areas of the world or do not have financial backing those things tend not to be as nice. But in any good well supported park, water, food and health care are not an issue.

Answer 2

Scientists really don't know why but a theory is that because there is less room they can't have it straight or it could get injured. i don't know, its just a guess.