Ron Sanford / Alaska Stock LLC / Corbis

Wolves are not supposed to be able to climb trees. Or fences. But a wolf named Virginia chose not to abide by nature's rules and escaped the Los Angeles Zoo in 1979 multiple times by ascending trees, climbing fences and walking along branches toward her eventual freedom. At one point, she eluded veterinarians and zoo officials for a month; they spotted Virginia occasionally and tried to subdue her with tranquilizer guns, to no avail. A zookeeper at the time joked that Los Angeles had the largest wolf exhibit in the world  4,000 acres (1,620 hectares) in nearby Griffith Park. It's unclear whether Virginia was ever recaptured.