While it's true that your blogging can -- and will -- be read by people from all around the world, have you ever considered blogging for the locals? If you're a pet blogger, chances are there is an animal shelter or rescue group in your area. There are probably even "meet ups" for people who love Poodles, Pugs, or Pomeranians, right? Are there agility groups that come to your neck of the woods? How about a dog or cat show? Who's writing about it? No one? Well, there's your niche!
If you've ever worked at a newspaper you can become a bit of a celebrity with the stories that you cover and the same goes for your blogging about local pet happenings. Do a Google search for animal-related events in your area -- choose a 50 mile radius -- then start making contacts. Send some emails, introduce yourself, send links to your blog, let them know that you're the go-to personal for all things animal!
From the small events to the large, you will have fodder for your blogging, make contacts within your local community which can then help you spread your influence to the larger pet community. Starting small, especially if you're just starting out as a blogger, is a fantastic way to build a reputation and grow your readership!