Primary difference between an animal's behavior and an animal being zombified:
No fear of death by hunger or death at all.
Stalking time is reduced by the will to eat and kill.
Depending on virus strand (advocating depopulation), the given animal fears killing, but bites, scratches, and throws up willingly.
The shit spray from Tiger's gun hole also infects you from the depopulation zombie virus. So a zombie tiger may pounce and spray out its arse to try to infect someone behind it. To the tiger, the virus tells it to say, "fuck you," instead of being full of rage. This gives an alien fear since raging impulses are present, but still barren.
Gorillas no longer tear you apart, as basic zombie strands do. Instead, they favor throwing you around with a desire to kill or feed. The virus makes it ignore deficiency of food, ignore the living human's life, and care; and increases playfulness. This causes it to throw, push, slap, or a jumping on one survivor, then jumping onto the next.
In other words, with or without modified zombie strands, animals would be superior deadly since they all are highly muscular if infected. A great indicator of the difference could be a game, or Gran-Theft Auto, where you visit zoos, or that you can, but the animals are normal. Later in the game, they are zombified. Then again, the game is better off taken place in Africa, since Eastern European/Asian countries should rarely have a tiger appear. That causes a lot of writing technique for a necessary entrance of a zombie tiger. Perhaps, they all would know not to be infected, unless the smell is simply delicious.