Rat

Western symbolism of the rat is almost entirely negative and much of it descends from plague, though the role of the rat flea in transmitting the medieval pandemics is now genuinely disputed, with several historians arguing for human parasites instead. Elsewhere the animal fares far better. In Hinduism the rat, or bandicoot, is the vahana of Ganesha, the remover of obstacles: a small creature that can gnaw through any barrier is a fitting mount for the god who clears the way, and the pairing is read as intelligence and persistence rather than filth. The Karni Mata temple at Deshnoke in Rajasthan houses and protects some twenty thousand rats as sacred, believed to be the reincarnated devotees of the goddess.

Beyond myth and plague, the rat has an outsized modern role as the standard laboratory animal of biomedical research, and the specific strain most widely used, the albino Norway rat descended from stock first bred for study in the early nineteenth century, has contributed to a large share of the twentieth century's medical discoveries, from the mapping of the nervous system to the testing of new drugs, an unglamorous but enormous debt owed to the same species reviled as filth in most Western folklore.

The rat is the first sign of the Chinese zodiac, and the standard folk explanation is a race: told that the order of the years would follow the order of arrival, the rat rode across the river on the diligent ox's back and jumped off at the finish to arrive first, a story read as cleverness rewarded over mere effort. As a birth-sign the rat is conventionally taken to mark resourcefulness, quick wit, thrift and sociability, and in the wider Chinese symbolic vocabulary it is associated with fertility and with wealth, since a creature that finds and hoards grain is a sign of abundance. The sign is paired with the first of the twelve earthly branches and the late-night hours around midnight.

Long before the black and brown rats of the plague years reached most of the world, the Pacific rat, kiore, travelled with Polynesian voyagers as a stowaway and sometimes a deliberate food source, reaching remote islands including New Zealand centuries before European contact; introduced rats of all species are now understood as one of the most damaging factors in island bird extinctions worldwide, since ground-nesting birds evolved with no defence against a mammalian egg predator, a conservation problem now addressed through large-scale island rat-eradication programmes.