This chapter recounts how sundry animals got their quirky traits. The explanations are all provisional, and any one of them could be overturned by new data at any time. But isn’t that the nature of science in general?

The topics were chosen mostly from evo-devo literature of the past decade. The animals are listed from A to Z, with some cross-referencing where necessary. Some of the more familiar animals may rekindle the curiosity we felt as children when we first saw them at the zoo or the circus or, for the smaller ones, in our own back yards. Others will be new to many readers, and some are so exotic that they might delight even seasoned zoologists. Overall, the menagerie shows that earth’s animals are at least as wondrous as any alien creatures ever imagined by science-fiction writers [468,553,2383].

Like the parade of pilgrims in Richard Dawkins’s The Ancestor’s Tale [504], each of the animals discussed here has its own unique story to tell. Sadly, some of those tales will be their last gasps as their habitats vanish [915,1539], and we will never fully learn how their features arose. Among the species most endangered are the gentle manatee [2376], the nimble cheetah [430], and the fearsome polar bear [1052]. Because the vignettes in this chapter are meant to be more informal, no lessons will be listed, but key concepts will still be set in boldface.