right now the despawning system for all the creatures is the same as that of vanilla mobs, which is pretty frustrating as the addon's gameplay revolves around taming creatures. if you found a creature u wanna tame for later and then leave the chunk then theyll disappear, unless they're aggro'd against you.
reason why im gonna try deal with this is because if you get knocked back by a wild tyrannosaurus roar youll be far enough from them to make them disappear, which is pretty frustrating especially since the only way to tame them is to hunt them for their eggs