I agree that Michael is an alpha. I think Burt used to be an alpha, but is now a beta. He pounded his chest and waved some branches around but in the end realized he wasn't up to it.

I can't remember if it was chimps or gorillas, but a documentary I saw showed an alpha being defeated by a younger one. They said that the old alpha often became the new alpha's beta. Sort of second in command and someone who had their back. After Burt handed the reins back to Michael, it was like they'd finally sorted their places in the hierarchy.

There are a lot of studies out there about what characterizes a socially dominant human. Being decisive, sure of yourself and your decisions (which is one reason that sociopaths sometimes make it into these positions). In small tribes though, it's supposed to be a lot more about consensus building. Moving unilaterally gets you booted.