Can animals be villains? I've heard of heroic dogs and horses (and military medals of bravery have even been awarded to pigeons!) but I've never heard of a villainous animal.
Villainy is a hard concept to tie down, so perhaps it's best to first think of evil - are there evil animals? Of course, some people needlessly view the ways of an entire species or family, usually a reptile, as evil - but to tar a whole group of animals as evil must surely be to dilute the meaning of the word so much as to be meaningless.
Intelligent animals can certainly lie. There are troops of monkeys that forage on the jungle floor, and if one spots something juicy in someone else's patch they occasionally give a warning call that sends everyone into the trees - leaving them free to go get it.
More obvious lies have been told by chimps and gorillas that have been taught sign language - and seem as prone to fibbing as most humans, though the lies are typically less devious. In one famous example there was a gorilla called Koko who had a pet kitten. Koko had a fit of temper in the night and ripped a heavy steel sink off the wall; when asked what happened, Koko pointed to the kitten and signed "cat did it".
Is it such a long way from the simple lies of gorillas to the deceptive games of human villains? We are all animals and the forces of nature and nurture are powerful ones indeed - so how accountable is anyone? I like to ask people who believe in the devil if he could repent and be good again. It perplexes them as they have to either give up on the idea he has free-will and therefore that he is evil (these seem intertwined), or give up on their belief he is fated to be the head evil dude forever.
Villains add to the rich tapestry of life and help create bonds in society - nothing brings people together more than a common enemy - that's why the highest sense of nationalism is in times of war.
So in conclusion, I've waffled and digressed a bit, and I had no clue where I was going when I started writing this, but it is past 3am so forgive me - I hope you just have some food for thought :)