More here on the ancient conserved rhythm, and the greater variability in H sapiens:
'Research on human laughter perception suggests that variable timing is perceived as more socially and emotionally positive than rigid, stereotyped timing. A laugh that shifts and accelerates and varies across its duration reads differently from one that ticks along like a metronome. Humans have developed, it seems, not just faster laughter but more expressive laughter in the purely temporal sense.

https://www.primatology.net/p/the-rhythm-in-ape-laughter-is-15?utm_campaign=post&utm_medium=web