I think Sligs are smart due to their high reflexes, in Abe's Oddysee, if they heard one footstep touch the ground they'd yell "Weak!" or something like that and they quickly turn and kill you before you can even turn around. But all in all, Sligs can be pretty stupid because they can fall into traps if you get them over to it.
And I do NOT understand their language in Munch's Oddysee (When they aren't possesed) they say stuff like "beh heh,so it's just allover the place" "So we guttha so we gettha?" "Ah Chum". What the heck kinda conversion is that, random gibberish or something.
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A little off topic, what about Elums? they're pretty cool creatures and yet they're still ignored in most if the games. It would've been awesome to hitch a ride on him in Stranger's Wrath so you could chase down and possibly even scare some of the outlaws, riding Elum could've even added new boss fight ideas such as riding down an escaped outlaw wanted dead or alive.