The Only Genus with Shared Bodily Rhythm?

Harvard University Press

I'm reading the magnum opus of my old Berkeley advisor, Robert Bellah, and finding it fascinating, but I do wonder about one bit of information that I've just read:

Rhythm, which is already evident in the simple reciprocal mimetic games that parents play with very young children, is the basis of group rituals that can mimetically define group identity and the roles of individuals within the group. Ours is the only genus with the capacity for "keeping together in time," and this biological capacity has been essential for the full development of mimetic culture. (Bellah, Religion in Human Evolution, 2011, pages 127-128)

By "mimetic culture," Bellah refers to the ability to mimic others behaviorally, which is necessary for passing culture down from generation to generation in species that lack language. Shared bodily rhythmic activity builds upon this ability, and this shared ability is important as a skill for a mimetic culture to 'create' society as a whole through rituals enacted together, according to Bellah, which requires not just imitative skillls but also "keeping together in time." Only our genus, "homo," has the capacity for this requirement of "keeping together in time," Bellah writes, but I wonder if this is entirely accurate. We know that whales sing to each other across great distances. Might they have this capacity for "keeping together in time" (a phrase borrowed from William H. McNeill, Keeping Together in Time). Susan Milius tells us in "Male Humpback Whales Sing Duets," Science News (October 23, 2009), that whales can sing together:

Danielle Cholewiak, a researcher for the Stellwagen Bank National Marine Sanctuary based in Scituate, Massachusetts . . . . undertook . . . song analysis [of humpback whales] while at Cornell University, which has a renowned flock of birdsong researchers. She adapted measurements used in bird studies to analyze the humpbacks' songs. For example, the whales repeat a phrase of notes several times in one block, or "theme," before moving on to another, and Cholewiak looked at how often the whales switched among these themes . . . . In . . . sound recordings, she found 14 cases in which a male sang alone for at least 45 minutes and then continued for another 45 minutes after another male started singing. Cholewiak noticed two changes in song when humpbacks sang together . . . . [T]he first singers switched more often among various musical themes when a second singer hung around. Also, the first males adjusted their songs so that the pair was more likely to sing the same theme simultaneously.

Bellah was speaking primarily of "keeping together in time" in terms of bodily movement as rhythm, but singing together and moving together rhythmically are surely connected, and I wonder if whales might display bodily rhythm together as well. I wonder if dolphins can also do so. They can mimic very well, and we know from captive dolphin performances that they can be taught to perform sychronous movements. Can any of these performances be considered "keeping together in time"? One could object that this is training, not coordination, but dolphins engage in coordinated movement in the wild. Do they ever engage in "keeping together in time" in the wild? McNeill, in his book Keeping Together in Time, states that dolphins' "coordination of movement" does "not involve the maintenance of a regular beat." Is this never the case? I don't know if dolphins 'sing' like whales, but the whales' ability to sing together raises the possibility that cetaceans might share the capacity for "keeping together in time."

Does any reader know the answer to these questions?