This is very vague, what so animals just got started to be as intelligent as humans? And then they all banded together and attacked? Well maybe, but if every animal on earth developed a society of their own and banded against humans, humans would be mince, dead, crushed and annihilated from the face of the earth, even if insects alone started a society and decided to wipe out mankind it would be a complete success.
Lets face it, humans are weak, weak as shit, the only thing we have going for us is having a good amount of long distance running and apposeable thumbs (which every other ape has) and how de we not know that they will create specialised weapons for eachother? Some species would be specialised as spies and others infantry, airforce, support, medical attention etc etc etc. and dont forget that there is over 1 quadrillion animals on this planet so we are vastly outnumbered, they would develop weapons, artillery and just overwhelm us with sheer force and numbers.
Humans are weaklings without weapons, and intelligent animals with rifles are even more powerful then before.
Im surprised by the amount of people who are a bit too arrogant and stupid to not realise that we are so ****ed, ****ed to andromeda and back.