ape
貜 centers on a large ape or monkey. The given meaning 'ape' is the core idea.
貜 combines 豸 (beast/animal radical) with 矍, which likely contributes the sound. The character is used for a type of ape.
The left side 豸 suggests a beast, and the right side 矍 looks like a pair of eyes under a roof with a hand holding something—imagine a large ape peering out from a shelter.
For キャク, picture a giant ape doing a 'kyak' sound as it swings through the trees: kyak -> キャク.