Are there other aspects of science?

Slapstick. Humour's related to sudden pain or being startled, stuff that's out of place. So we laugh because life hurts. Tragic.

Well, now that we've discerned the evolutionary mechanism behind crude humour, I can safely include "poo" in my vocabulary and say that I'm doing science!

Pops and clicks. Like being lightly bludgeoned. Pain and dealing with it are rarely far away.

I recall reading about something like that, too. There are funny sounds, and non-funny sounds. For example, the word "mute" is hardly humourous in sound nor meaning, but change one letter and you get "cute" and suddenly, completely different.

Now that I think of it, in general, "softer" sounds are not as funny, whereas letters like K, C, P (which have a "sting" to them with the ee sound) are all over the words you've mentioned.

Monkeys can get old, though comedians still tend to lean on them. I once read something about the phonetics of funny that suggested that monkey was intuitively funnier because of the k sound. (The bare-toothed ee at the end is also a nice grimace-or-grin segue.) Other funny words with k sounds: kumquat, guacamole, Clem, Kadiddlehopper, schmuck, kookaburra, wocka-wocka. The ear does get tired of that sort of thing pretty quick, though.

When all else fails, including a ridiculous looking animal in an analogy or simile is a sure recipe for instant funnies. Monkeys are always good candidates, but they get boring over time, don't they?