Power
You have the power to save lives, but you may also be asked to end them.
In some states and counties you are licensed to use a firearm, and in some cases you'll need it. You might be attacked by bears, coyotes, or bobcats; or you might have to use your weapon on an animal that is wounded beyond repair and is suffering.
You may also have to euthanize animals if you work for a kill shelter. You will have to go through specialized training to do this, but it's still a hard thing to do. If you don't think you have it in you, opt for a no-kill shelter and spare yourself a lot of grief and heartache.
That's the Dark Side of your power. But the forces of good are yours to wield, too.
You're an officer of the law and you can give out tickets to people or arrest them for animal cruelty. Animal abuse laws vary from state to state, but abusers can be fined up to $5,000 and/or spend five years in jail for extreme cruelty to animals (source).
You also have the power to save lives on a daily basis. You can rescue animals living in neglectful and abusive situations and find them homes with happy, loving families. You can protect the public from vicious animals. You can issue noise violations to people who have neighbors complaining that they can't get any peace and quiet. You can reunite lost pets with their owners.
Go put on that cape and start saving the day.