dots in the shark

A single bark ought to suffice -- it would alert other dogs, or remind a small creature to be afraid of the dog. Successive barks expend calories needlessly, and distract the dog from other productive activities. I see cost with no benefit.

The only potential benefit I can imagine is sexual advertisement. Advertisement is from a public finance perspective inefficient, but from an individual actor's perspective it is necessary, and that's the level of decision-making relevant to nature. Hence peacock's tails, headbutting and other ostensible design flaws.