I realize that this is hardly traditional HN fair, but watching amazed me. I had no idea that bubble rings could exist, or that dolphins would play with them like this.
I'm more amazed by the fact that dolphins mastered the technique of creating bubble rings. And if the description in this video is to be believed, they also pass on this technique to other dolphins.
Individuals of many species are capable of copying the behaviour of another individuals (usually of the same species) by observation. The other primates are the most well-known mimics ("monkey see, monkey do"), but most mammals and birds do this. We like to think we're special in this respect, but we're really not.
Birds, for example, learn features of their songs from other songs they hear. Over time, these features accumulate in a bird's repertoire, and even develop into a dialect for an area. See http://en.wikipedia.org/wiki/Bird_song#Learning
Another example in birds is the behaviour of crows in Japan, who have learned to crack nuts by leaving them in traffic at intersections, waiting for the cross signal, then retrieving them. See http://www.youtube.com/watch?v=BGPGknpq3e0
This is the first example I've heard of a "play" behaviour being learned, but what can I say? The life of a captive dolphin would be boring; a new way to pass the time would be a useful thing to know.
It's not the kind of thing typically posted, and I certainly don't want cute animal stuff on here in general, but I think this video is, if not appropriate for HN itself, then at least appropriate for the HN demographic. I can't imagine how anyone interested in intelligence and in the mind could not watch this video and question whether dolphins are sentient. Maybe it's similar to a dog fetching a ball or whatever, but I think things like that require training, and I'd assume dogs get an instinct-based payoff (maybe it's similar to chasing prey) and/or payoff from the compliments of their owners. The dolphins seem to be doing this of their own volition, for their own entertainment, and I can't imagine how this behavior could have been trained.
(I don't own a dog, and don't have much experience with them, so take my comparison with a grain of salt.)
While diving in Monterey, I came across a harbor seal who had found a float on a string, anchored so the float was about 3 feet off the bottom. (It looked like it was part of some experimental aparatus.)
She was batting it around, clearly playing with it.
(Unlike other seals we ran into that day, she was uninterested in people. She reacted to us when we swam up but soon went back to playing with her toy and ignored us.)
Yeah, hmm...looking back at my comment I am not quite sure what I was getting at. Wishful thinking is probably the culprit; I like learning languages, and I think it would be awesome to learn one day to communicate intelligently with another species.
Seals aren't all that useful as shark detectors. They're usually not around and they look just like attacking sharks when they play their "swoop" game. (They find this quite funny.)
They also play "hide", which often consists of putting their head behind a rock and peeking around to make sure that you're coming by. Yup, they leave their huge body exposed.
