I've found an injured wild mammal. What should I do?

If you can pick up the animal:

If you cannot safely pick up the animal
An SF ACC Officer will rescue the animal. Call San Francisco Animal Care and Control (415) 554-6364. Be precise about the location of the animal to help the Officer locate the animal, especially if no one will be there when the Officer arrives. Tell the dispatcher as much as you know about the situation, such as how long the animal has been there, anything you know about the cause of an injury, the direction it came from, etc.

Please stay to protect the animal from harm or disturbance by dogs and people until a SF ACC Officer arrives. Frightened animals may run into traffic or leave the area and be hard to relocate. Keeping an eye on the animal if it moves will make it easier for the Officer to locate, increasing it's chances of getting care. If you cannot stay, try to find someone to protect the animal from disturbances, and note if it's location moves, until the Officer arrives. Covering an animal with a box or laundry basket, when possible, will reduce visual stress and chances of animal running off. Always approach a wild animal slowly. Fast movements scare them.

Opossums are marsupials, carrying their babies in a pouch, like kangaroos and koala bears.
A mother opossum that has been hit by a car may have babies in her pouch that could survive with care. Place baby opossums up in a box or paper bag, with a towel or T-shirt if you have one handy, and transport to SF ACC or call for a pickup asap. Keeping babies warm is critical to their chance of survival. Check for young opossums in nearby shrubbery. If they were with their mother, they will not survive without care.

If you have a wild mammal in your possession:

Reduce stress to wild animals by not talking or playing a radio in their presence. Domestic animals are predators of wildife, so please, keep wildlife away from domestic pets. (Just the presence of domestic animals is stressful to wildlife.)