Posted by: Wendy Gardner, Zookeeper Photos by Wendy Gardner/Woodland Park Zoo Who weighs nearly 100 pounds, belongs to a family of mammals (Macropodidae) whose name means “big feet,” has a long, muscular tail that helps with balance, turning and support while resting, and cannot walk backwards? Harry gets a food reward for cooperating with his treatment. That would be Harry, our male wallaroo who lives in the zoo’s Australasia zone. Harry came to Woodland Park Zoo in October 2008 as 2.5-year-old sub-adult, a term we use to describe juveniles that have not yet reached sexual maturity. In December of 2008 he weighed about 62 lb (28 kg), but as of June 2013, the now adult wallaroo weighs just shy of 100 lb (44 kg). That’s a good weight for him, but that size and strength means we do not want to have to hand catch him if he were to ever need medical attention, both for our own safety and to prevent stress for him. We decided using operant conditioning to get Harry not o