Lizards in Puerto Rico are evolving feet that better grip surfaces like concrete, carrion crows in the Japanese city of Sendai have learned to use passing cars to crack nuts; and Europe's urban blackbirds sing at a higher pitch than their rural cousins, to be heard over the din of traffic. How is this happening? Taking an up-close look at just how flexible and swift-moving natural selection can be, the author of Nature's Nether Regions suggests in this wry, illustrated overview that the wildlife sharing overpopulated urban spaces with us is not just surviving, but finding new ways of thriving—from dumpster-diving to developing new camouflage.