Marine biology is hard. We (scientists!) literally cannot know what our subjects are doing all the time- we (Tim and Team Sousa) are lucky enough to have marine subjects that have to breathe air and come to the surface fairly frequently, but in a rather neat and frustrating exchange they also have a wide home range and can only be spotted effectively during the day, and really only days with good weather. So much of what they’re doing goes unnoticed or unseen, underwater or under cover of darkness or simply when we’re not looking directly at them. Sousa sahulensis has never, to my knowledge, been kept in captivity, nor could we ever say we’d seen them behaving “normally” and/or with a complete range of behaviors if they were to be so kept. Marine biology- it’s like detective work, following incomplete bits of information to try to piece together a whole story. It’s constructing specific questions, ones that we can answer given the limited observations we can get.
However, we’re out on the water as much as we possibly can be- every relatively windless day, five to ten hours at a time- and we see a lot of interesting behavior. For example, “banana pose,” in which a dolphin arches its back, rostrum (nose) and dorsal fin in the air. It’s a goofy-looking behavior, potentially adopted by males as a social or courtship display. Another example is one that I’ve heard about but haven’t yet seen- “sponging,” which in this case* is another potential courtship behavior, in which a male dolphin selects a sponge on the reef (quite a large one, too) and presents it (at the surface, presumably, since Tim’s seen it) to a female. He then adopts a banana pose. How romantic.
I don’t know that I’d consider any of this to be weirder than human courtship behavior, though. If you liked it, then you should have put a sponge on it- what’s the difference? After actually having visited a bar last Friday on my birthday (WHO AM I) I really could not argue for any sort of logic in the ways that young humans choose to behave (and I’m including myself here, don’t get me wrong). Presenting alcoholic beverages to other individuals or groups, rhythmic full-body movements to pre-recorded vocalizations, displays of colors and other physical attributes… Sponges seem more straightforward. Take note, lads.
*”Sponging” can also refer to another really cool dolphin thing- down in Shark Bay, where some other dolphin researchers have been conducting exhaustive focal follows and continuous analysis of several individuals’ behavior, Tursiops aduncus have been seen with sponges over their rostrums, using the squishy animals as shields against anything poky they might encounter while searching the benthos (the bottom, in this case sandy) for food. They actually teach this technique through generations, demonstrating cultural inheritance and general braininess. Ahh, I remember the days when my mom taught me how to forage successfully and keep my nose out of trouble. As far as I recall, grocery store watermelons are supposed to sound hollow, cantaloupes are supposed to be heavy (as is corn on the cob) and most everything else is just supposed to be unbruised. Put my hand under cold water if it gets burned, and while traveling on airplanes, always wear a scarf. Thanks Mom!