Darwin Comes to Town by Menno Schilthuizen
The Earth is human-dominated; humans consume one quarter of all plant-produced food and half of the world’s fresh water. In 2007, the number of people living in urban areas passed the number living in rural areas, and by 2030, nearly 10% of the planet’s land mass will be urbanized. Is Dutch ecologist and evolutionary biologist Menno Schilthuizen concerned about the plight of the natural world? Not particularly, and in Darwin Comes to Town he explains why, beginning with the ants.
Myrmecophiles are insects that make their homes in the nests of ants. There are thousands of species that have evolved to this purpose, and the reason this is so is that ants are ecosystem engineers – they modify and create ecosystems, much like coral, beavers and, of course, humans. Schilthuizen wants readers to understand that cities are as natural a phenomenon as beaver settlements, coral reefs and ant nests; he begins Darwin Comes to Town by tracing their growth from modest farming settlements to the proliferation across the planet of today’s megacities. And as the myrmecophiles adapt to ant habitats, so do the anthropophiles evolve to live in our concrete jungles.
Meandering in and out of specific cities with examples of various anthropophiles, the author calls attention to how these animals came to live in cities and some of the attributes that make cities hospitable to their non-human inhabitants. In many cases, these inhabitants are exotics that were brought by humans to their urban homes. For instance, port cities such as Singapore and San Francisco abound in non-native sea creatures that arrived via ballast water – water that ships pump into their hulls to improve balance and dump at the next port.
In one example, Schilthuizen details the plight of the Indian house crow whose migration to the chilly climes of the Netherlands sparked a skirmish between Rotterdam’s provincial government and a bird-loving opposition. The Rotterdam house crow conflict launched a specific group of urban naturalists devoted to the preservation of the crow and to the principles of urban biodiversity, a phenomenon that Schilthuizen tells us is based partially on the diversity of habitable places in the urban environment.
There is a house sparrow population, for instance, that makes its home in the mass of bicycles parked outside the train station in Schilthuizen’s hometown of Leiden in the Netherlands. The house sparrow’s natural habitat, thorny thickets of trees and bushes, make the tangle of metal rods, posts and spokes outside the station something for which the bird was pre-adapted. In fact, Schilthuizen tells us that the first species to move into cities are usually those that are pre-adapted to urban niches that resemble their natural environs. Pigeons, that bane of city dwellers, happen to be descended from wild rock pigeons, who roost on high rocky cliffs, not dissimilar from those we’ve erected in our cities.
My favorite bits of Darwin Comes to Town are the stories Schilthuizen tells about the incredible adaptations of his urban subjects – crows that use our automobiles to crack walnuts, catfish that snatch pigeons from slippery city riverbanks, and Mexican sparrows who line their nests with discarded cigarette butts, deterring mites with the chemicals therein.
Throughout, the author’s language is playful and colorful. He alternately describes standing gene variations as a palette from which a species can choose in making its brush strokes and, in a banking metaphor, as a specie’s “genetics savings” or “evolutionary capital.” He also peppers his prose with words like “unfankle” and, as an adjective, “Rube-Goldbergian.” Lovers of nature and of a well-crafted story will find Darwin Comes to Town both informative and enjoyable.