Reproduction
Skeleton
Vision
Culture
Government
Skeleton
Pred-skull-1
Not much is known about the Yautja skeleton, it has not been seen in full in any of the films. In Predators a Yautja skull was seen in the Super Predator trophy-site.
(Alien vs. Predator 1990, comic) Doctor Miriam Revna noted that Dachande had four cracked ribs.
(Predator: Concrete Jungle, game) Scarface collects the skulls of his three brain-washed clan-brothers, and Hunter Borgia has a Yautja skull as a, presumably decorative, part of his own armor.
Vision
It has been demonstrated clearly in every film that the Yautja naturally see on the infra-red bandwidth of light, most likely exclusively. This has been shown to be both a strength and a weakness, Dutch was able to avoid being seen by covering himself with mud in the original film, and Royce was able to blend in with another heat source.
Their vision can be altered or augmented with their masks, several different vision modes have been seen but their function has not been clearly defined. It should be noted that when the Jungle Hunter removed his mask his vision changed greatly, this has not been seen in any other film. there are numerous theories in the fandom as to why this is, the predominant one being that the relative temperatures of the jungle were very high and his mask aided in filtering them, this is supported by events in Predators.
Miscellaneous Biological Information
Various miscellaneous biological aspects have been given throughout the various published predator media that do not fit strict categorization.
(Alien vs. Predator 1990, comic) Doctor Miriam Revna notes that they have a completely different cell structure from the Xenormorph facehugger.
(Predator: Forever Midnight) The Hish possess what is called a "Kill Gland" a small cherry-red gland located beneath their clavicle that produces a dangerous hormone that causes the Hish to launch into a homicidal rage