A Very Serious Lore Question

[Cluck]

Well the obvious answer is that Dalaran used to be on the ground. But a retort is: why are these creatures still alive? How are they still alive? The world may never know...

As with many real world creatures that appear in Azeroth, the squirrels of Azeroth are different from the squirrels we see here on Earth. Azerothian Squirrels actually reproduce through eggs, and much like roaches, killing one normally will usually leave at least some of the eggs alive, meaning there's always more squirrels.

[Shadowmelded]

Maybe it wasn't their time to die yet either and they just run back to their corpses each time?

[kbk]

Well that would explain how they continue to comeback, I mean I killed a fair few of the vermin but what do they eat? There aint no trees by the fountain. Maybe they gnaw on unsuspecting undead legs... but would that imply they've turned omnivorous / carnivorous?