Depends what kind of wildlife you're talking about. If you mean in zoos and the like, yes its fine. If you mean "real" wildlife, then very likely no. You'd want ~400mm for that, which means looking to the sigma 150-500 OS or 120-400 OS, or if your budget allows (which I doubt from your post), the canon 100-400.
Unless of course you know you'll be able to get relatively close to the wildlife, then the 70-200 shines. Here are some zoo/safari shots with it:
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Just to show you what I mean about the 70-200 not being enough for real wildlife:
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That bird was about 40m away if I recall, and this was shot with a 1.4x TC, so 280mm. My intention was actually to photograph the bird, but since this was the biggest I could get it in the frame, I went for this shot instead.