overnment officials in Australia are complaining about wallabies — small marsupial mammals that resemble kangaroos — who are invading poppy fields in order to get high off the narcotic effects of the plants. Roughly 50 percent of the world's legally grown poppies, which are used to make morphine and other pain-killing drugs, come from Australia. Lately, strange crop circles have been appearing in the fields, and are being blamed on the marsupials' unseemly behavior. "We have a problem with wallabies entering poppy fields, getting as high as a kite, and going around in circles," says scientist Lara Giddings, as quoted by BBC News. "Then they crash." But wallabies are just the latest in a long and ignoble list of animals who seek out psychoactive drugs and alcohol, apparently for the same reason many humans do. Here, a look at the biggest stoners and drunks in the animal kingdom.