From Plague-Carrier to Ganesha's Mount

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.