Main Canon ---------- Within the main canon there are no examples of the Borg successfully assimilating anything other than [sentient, bipedal, humanoid creatures][1]. That being said, there's no reason to assume they *couldn't* assimilate them, if the mood took them and they saw a benefit in doing so. Otherwise they'd just **ignore them or kill them if they presented a threat.** EU Canon -------- Within the novel [The Return][2] (written by none other than William Shatner) PIcard encounters some **assimilated dogs** > Two dogs—sleek Dobermans, pets of the personnel who had been assigned > here, no doubt, trotted past. But they did not stop to investigate. > **Bioneuronic implants studded their skulls. Biomechanical tubes were > grafted to their chests.** > > One dog turned to look at Picard as it passed. One eye clear though > expressionless, so unlike the breed. **The other eye had been replaced > by a laser sensor.** [1]: http://scifi.stackexchange.com/questions/20274/why-are-there-no-non-humanoid-borg?rq=1 [2]: https://en.wikipedia.org/wiki/The_Return_(Shatner_novel)