Deep in Contemplation

Humans tend to stroke their chins when contemplating something of great profundity. I assume that the siamang equivalent is to stroke your inflated throat sac when contemplating at whom you would like to throw your next steaming pile of excrement.

Thanks for clueing me into the siamang, Lorri. I've neglected this vine-swinging primate for far too long.

Photo source: knox9000