@Tokanova Of course it must be a cat. They are highly lethal on their own (especially against farmers as you note) and they are cute (which is apparently good for team cohesion as the Paladin wanted a cute companion to be added).
And if you stack the rangers bonuses on the cat, it becomes more hardy (and dangerous), and if you throw it at your opponents they don't get any free strikes on it while it comes into killing range.
I mean, there's a reason for why Belkar Bitterleaf (of Order of the Stick fame) went with a cat for his animal companion (and it's not only because he could be a bit emo at times). Come to think of it, Belkar also tried to tame a Tyrannosaurus (and briefly had such a mount), so this entire chapter might well be a homage to that halfling ranger XD