Female walrus and calf, Greenland
One evening, many years ago, I visited SeaWorld in Florida (earlier that day I was given my 'free' SeaWorld ticket in return for sitting in front of a psychotically enthusiastic time-share salesman and saying “no” for two hours. As I behave like this in most social situations it wasn't too onerous a task. There was even a slap-up breakfast – much appreciated after all that socialising).
There were Californian sea-lions bouncing balls on their noses and the usual Delphinidae leaping through hoops, derisory activities (literally) for such intelligent animals. I was herded with the other visitors from exhibit to exhibit while people with microphones strapped to their heads educated us (by telling us about the animals' environment - not the fish tank they lived in, somewhere else) and entertained us (by coaxing the inmates to exhibit aberrant behaviour in return for food). After a while I decided to see what the animals did when they weren't performing. I retraced my steps and quickly found myself in near darkness as only the area where a particular presentation was being made was illuminated. A concerned member of staff came trotting after me, he'd assumed I was looking for a lavatory or deranged, when I explained my mission he seemed at a loss as to what to do as my breach of SeaWorld etiquette wasn't quite enough to warrant arrest. Eventually he returned to the spectacle (he had grown agitated when the light show began to move away) and I was able to carry on stumbling through the herbaceous borders. I found a couple of tanks but, in the gloom, it was impossible to ascertain what was going on within. Reluctantly, I decided to rejoin my fellow visitors. It wasn't difficult to locate them; an oasis of laughter and light surrounded a magnificent walrus that was proving to be refreshingly unbiddable. The massive pinniped just floated in the eerily lit water like a slug in a lava lamp while its 'trainer' tried in vain to get it to do something. And then, in apparent response and much to the delight of the children and myself, its bowels moved. A brown cloud suffused the neon blue of the aquarium, swirling and expanding and causing a man with a microphone strapped to his head to hurriedly switch off the lights and suggest we see the stingrays. It occurred to me that the walrus's performance was the only natural behaviour I'd seen since I'd entered the place.