Critical Research Failure: All three games refer to the apes as "monkeys," which anyone can see is wrong since they quite obviously have no tails. And they're not hiding them in their pant legs, those things are custom-tailored for the apes, according to the second game. It's especially baffling that this error persists for three installments, while the title (APE Escape) gets it right all along.
Well, they are based off the Japanese Macaque, which are also called snow monkeys. They don't have tails either.
Why is the Metal Gear Solid-inspired minigame called "Mesal Gear Solid"? What does "mesal" mean here?
I believe that in the japanese version it's called Mesaru Gear Solid. It's supposed to be a pun because "Saru" means "monkey". And that's why it's called Mesal Gear Solid in the English version. That's why you see a lot of monkey names that have "Sal" in it (Like Sal-3000 or Salulu).