Well, as it stands you don’t have any way to dodge any sort of projectile in the game at the moment, so the point is somewhat moot. By the way, do you have any idea how to actually code these or are you just tossing out ideas? Nothing wrong with either, certainly, but your monster has a higher chance of getting added if someone can code it easily and without adding too many mechanics.
Honestly, I’d probably go with fleshing out the scavenging detail, it covers a niche that the other wildlife don’t. There are more than enough giant spiders in the game as it is.