From law.com, a profile of Bruce Wagman, animal lawyer and co-author of the Animal Law casebook He says doing animal law was "the only epiphany I've ever had."
Wagman recently won an injunction against breeders in North Carolina who allegedly kept their animals in horrific conditions. The action was brought under a North Carolina law which grants a civil remedy to anyone, including non-owners. As one recent article noted, the civil remedies provision has been chipped away at since it was codified, but remains a unique tool for animal advocates. If you have Lexis or Westlaw, see William A. Reppy, Jr., Citizen Standing to Enforce Anti-Cruelty Laws by Obtaining Injunctions: The North Carolina Experience, 11 Animal L. 39 (2005). Otherwise check out this abstract.