How many times does the Torah mention Wild Animals?
None.
The Torah only uses the word ערוב - multitude when describing this plague. There is no mention in the text that this plague was comprised of animals. This is why there is a machlokes In the Medrash (11:3) whether this plague was comprised of a crowd of wild animals (Rabbi Yehudah's opinion), or if It consisted of a swarm of wasps and mosquitoes (Rabbi Nechemyiah's opinion). [The Medrash brings a proof to Rabbi Yehudah's opinion from looking at how the plague ended. By the plague of the frogs died in the streets (8:9-10), and the earth reeked from the dead frogs. When it came to this plague, it says that they were completely removed from Mitzrayim (8:27). Why did they not die in the streets as the frogs did? According to Rabbi Yehudah's opinion it makes sense that the wild animals did not die in the streets, since otherwise the Egyptians could derive benefit from the skins. Whereas according to Rabbi Nechemiyah's opinion, the swarm of flying creatures should also have died in the streets like the frogs, as there is no use for their dead bodies. Therefore, the pesukim seem to indicate that we are dealing with wild animals.
What could save an Egyptian from the plague of the Wild Animals?
If the Egyptians would be in fortresses or towers, they would be saved {Bechor Shor). Likewise, if they would escape to Eretz Goshen (where the Jewish people resided) they would also be saved (Ramban, but see Ralbag that disagrees). Also, the shepherds managed to defend [themselves and] their animals in the fields from the Wild Animals, presumably using their sticks as their defense. This is why the Torah stresses that in the plague of Pestilence, even the animals in the field would suffer, as the shepherds would be powerless to come to their protection (Chizkuni to 9:3).
