Rabies is a complicated disease with different strains that affect different animals species differently, and their prevalence waxes and wanes over the years for reasons not always obvious to us.
The announcement that a coyote strangled by a New Hampshire dad after it attacked his toddler was rabid (see here) was a little surprising because coyotes do not seem to be a major carrier of the disease. Even more surprising, local officials say they fear that several affected coyotes are in the Exeter area.
In general, bats are the mammal that causes the most human rabies infections around the country. Along the East Coast, raccoons are common carriers because that strain of the disease is more common here. Skunks are common carriers in the Midwest and other animals are the main culprits elsewhere – mongoose in Puerto Rico, for example.
Before rabies vaccinations became mandatory, by far the most common species to infect humans were dogs.