Wood rats (Neotoma fuscipes, sometimes called pack rats or trade rats) are native to San Mateo County and frequently live in wooded areas near creeks and streams, where they make large, elaborate nests of twigs and leaves. These nests often provide shelter for other species, including deer mice.
Woodrats are similar in appearance to roof rats and Norway rats, but with larger ears and furred tail (though not fluffy, like the tails of squirrels).
They rarely infest occupied homes, but may occasionally cause nuisance by leaving droppings on porches and decks or by stealing small objects left outdoors.
In California, woodrats are a reservoir species for Lyme disease. However, they do not transmit the disease directly to humans; Lyme disease is transmitted by tick bites.