Just a couple thoughts on dolphins, in light of Kate's most recent post:
Dolphins are actually a lot like hyenas. They both live in fission-fusion societies, which means they live in a large social group (in the hyenas' case, a clan, which can have as many as 80 individuals) but spend most of their time in fluid subgroups. These subgroups can have anywhere from a lone individual to many, and the individuals may vary. So, for example, Morpheus (my favorite hyena) may spend this afternoon with Pan, Samburu, and Monroe (subgroup of 4), but hang alone in the evening (subgroup of 1). It's rare for an entire hyena clan to come together at the same time, despite them all being in the same social group. The same is true for dolphins—a social group may have a pretty clear territory in which everyone stays, but you're not likely to see the entire group together at once. So it's possible the various groups Kate saw were all part of the same larger group, and what she was seeing was multiple subgroups coming and going. (It's also possible that they were from different groups entirely, or even different species—interactions between different species of dolphins aren't uncommon.)
But the similarities don't stop there. Both dolphins and hyenas are extremely gregarious, as I just discussed, and they're each near the top of their respective food webs. They also both have very large brains relative to their body size (compared to most other mammals), making them adept at completing cognitive tasks (remember Kate's post on the puzzle box?).
In fact, one of my dissertation chapters was inspired by a phenomenon I saw in male bottlenose dolphins. Male dolphins form "pair bonds," which is basically science-talk for bromance. (Oh man, I am calling dibs RIGHT NOW on being the first person to ever publish a paper with "bromance" in the title—Nature reviewers, get your pens ready.) Two males will form a bond that's so strong that they spend as much time together as mother dolphins spend with their calves (re: almost all of it). They forage together, travel together, and even court the lay-dees together, giving a whole new dimension to the term wingman. So essentially, I'm asking if male hyenas do the same thing. Updates to follow on that one.
Anyway, given the similarities between dolphins and hyenas and the financial success of "swim with dolphins" programs worldwide, perhaps Fisi Camp is sitting on a goldmine here. Anyone interested in a "run around with hyenas" program? (Disclaimer regarding prepositional confusion: "around with" can also mean "from," as in, "for your life.")