Walking Stick Bug, Cincinnati, Ohio, 1993 Photograph by Michael Nichols A female Macleay's specter stick insect pauses on a branch at the Cincinnati Zoo. Indigenous to Australia, these large, well-defended arthropods are covered in tiny spikes and can reach 6 inches (15 centimeters) in length. (Photo shot on assignment for, but not published in, "New Zoos—Taking Down the Bars," July 1983, National Geographic magazine)