Ants, one of the smallest of all the animals, come highly recommended by E. O. Wilson, a biologist who studied them.
Born in Birmingham, Alabama, in 1929, he said in answer to potential critics of his famous specialty,
For a skeptical audience who says, '. . . how could studying ants be very important?' Well, let me tell you, ants are the dominant insects. They make up as much as a quarter of the biomass of all insects in the world. They are the principal predators. They're the cemetery workers. Ants are the leading removers of dead creatures on the land. And the rest of life is substantially dependent upon them. In many environments, take away the ants and there would be partial collapses in many of the land ecosystems. Take away humans, and everything would come back and flourish. But I don't want to go down that down that road for a broad audience.
(According to the Writer’s Almanac, the source of info here, Wilson’s books include The Theory of Island Biogeography (1967), Sociobiology: The New Synthesis (1975), In Search of Nature (1996), and most recently, The Leafcutter Ants: Civilization by Instinct (2010).)