The artist Nick Cave is a collector. Or, rather, a collection. Like the rest of us.
That, in a nutshell, is the message of “Mammoth,” an exhibition at the Smithsonian American Art Museum that is anything but tidy and whose centerpiece, true to the show’s title, is a 700-square-foot light table covered in a couple of junk shop’s worth of knickknacks and gewgaws. Taken as a whole, this show — which also features sculpture, video, photography and installation and a wearable woolly mammoth — is a kind of self-portrait.