In his provocative new book, Zoos in Postmodernism: Signs and Simulation, marine biologist Stephen Spotte lumps together public aquariums and zoological parks (which he collectively calls zoos) and treats them as cultural derivatives assessable using semiotics (the study of signs and their meanings) and Baudrillard's models of simulation. He concludes that only modernist zoos can exist in postmodern times, making captive animal displays anachronistic. Today's zoos are thus reminiscent of an era generally agreed to have ended with the 1950s. Unable to evolve and compete with contemporary entertainments, they can only be spectacles viewed passively.