Nigel,
As I mentioned in another thread, people who post pictures on this forum are strongly urged to give as much detail as possible about the camera settings used, the equipment used, and the reasons for the photographic decisions which were made. This allows for much greater potential, both to inform readers about options and techniques, and for readers to offer substantial criticism. Please do feel welcome to add this information, and please keep this in mind, for future posts. Also, it would help if you could give us some direction of what kind of comments you are looking for.
The first picture is not focused. The first one also crops too tightly (for my taste), where it cuts off the tips of the the tiger's ears. In fact, I don't see much sense to the way it is cropped, at all. The second one is also cropped too tightly for my tastes.
Having now looked at several of your pictures of squirrels and tigers, I'd suggest a few things:
1) Be more conscious and purposeful in your framing decisions.
2) Be more careful and purposeful about where you focus, and why.
3) Learn about color balance.
Your pictures also leave room for discussion about inspiration, purpose, and communication. However, we can get to that, later. I'm choosing to address the technical issues, first. (Ultimately, they are inextricably intertwined, but... a little at a time.)
Mike
www.mikespinak.com