I actually think you make a convincing argument and I will concede that it probably depends on the animal.
No, it does not depend on the animal, it depends on who is training them and what ethics that they have.
For example making a bird fly from one high perch to another one which you often see in bird shows is not a lot different to their normal behaviour. However making Sea Lions do comedy acts and making Whales and Dolphins do what they make them do isn't the same thing.
The last whale I've seen performing in captivity was at Windsor Safari park and that was many years ago. I've seen Dolphin acts and they consist of Dolphins leaping out of water and doing summersaults. Last time I seen Dolphins in the wild (when I used to work on the cruise ships) they did just that, they leap out of water and do summersaults.
Don't forget that Dolphins are very intelligent animals that need stimulation, they are closely related to dogs.
Both my local Zoo's have animal displays including sealions, birds as well as mammals. None of their animals are trained to do tricks. Most of their animals including the giraffes, elephants, big cats, rhinos are all target trained (ball on a stick) to respond to positive reinforcement (clicker, bell, whistle sound) followed by a reward (treat/food). They do this in addition to what I mentioned in my last post, to bring the animals in, move them to another section of the enclosure, weigh them etc... Sealions are also trained to fetch object from the bottom of the pool. Say for instant, a member of public drops their phone into the water, the sealion can safety retrieve it, other wise if they weren't trained to do this, they might eat it which would be harmful to the sealion.
The public displays are not there to entertain the crowed, but are there to demonstrate what goes on behind the scenes with regards to their day to day training, as well as to educate the public of their natural behaviours.
If you do find that what they do is funny, it not because they are trained to be funny, but us humans find that what would be considered their natural behaviour, amusing. At one of our local Zoo, a red legged seriema is given a rubber snake, the seriema would pick up the rubber snake and whack it onto the floor. As funny as this looks, with the audience laughing, this is a natural behaviour of the bird.
Sealions are funny animals to watch naturally. Watching a sealion talk into a microphone may not appear natural (BTW our local Zoo's won't demonstrate anything like this or do anything that humanise the animals) by which is achieved by smearing food onto the prop microphone and all the sealion is doing is licking off the food with a voice over giving it the impression that the sealion is talking. Licking food of any object is a natural behaviour.
Like I said in my previous post, nowadays most reputable animal trainer will have moved on with their ethics and will only demonstrate natural behaviour or anything that would be a benefit to the animal as oppose to entertaining a crowd.
