Brilliant Timing: Evolutionary Biologists Rosemary and Peter Grant

By Ellen Gilbert

Screenwriters and movie producers take note: here is a great story that takes place on a remote island: the true-life adventures of Rosemary Grant and Peter Grant, the British-born, Princeton University-based evolutionary biologists.

That said, their new book, 40 Years of Evolution is unlikely to be optioned for a movie. Published by Princeton University Press, it teems with statistics, graphs, charts, references, and technical details that document their remarkable study of fi nches on Daphne Major, a small volcanic island in the Galápagos. Although the Grants say that they “have designed this book for students, educators, and others to read for enjoyment and inspiration,” the Princeton Public Library does not yet own a copy; Princeton University’s Lewis Science Library does. Moviemakers would be well advised, instead, to consult with science writer Jonathan Weiner, whose 1994 book, The Beak of the Finch, visits the Grants mid-career. More recently, Weiner’s New York Times essay, “In Darwin’s Footsteps and Beyond,” uses the publication of 40 Years of Evolution as an opportunity to bring their story upto- date.

The phrase “long term” applies here. B. Rosemary Grant and Peter R. Grant are both 77 years old and have been married for 52 years. When they began their work with a cadre of students on the small Galápagos Island of Daphne Major in 1973 they planned to stay about two years. “Their goal,” as Weiner tells it, “was to study finches in the genus Geospiza—the birds that gave Darwin some of his fi rst inklings of evolution by natural selection—and to try to reconstruct part of their evolutionary history. Instead they made an amazing discovery.”


Taking Darwin’s Origin of Species by Means of Natural Selection, which they describe as “a manifesto of cardinal evolutionary principles,” the Grants set out to observe adaptive radiation (i.e., diversification as a result of an event) among what are actually known as “Darwin’s finches.” Using ecological, behavioral, and genetic data (song recordings, DNA analyses, and feeding and breeding behavior) to measure changes, they succeeded in showing significant differences in average beak size and shape over the years. What has been described as their “’most spectacular discovery,” however, appears to be a new species of finch, differing in size, song, and other characteristics. In his review of the new book, British zoologist Tim Birkhead notes the isolation and inhospitable nature of Daphne Major, but says “the payoff” is in research that “furnishes some of the most compelling evidence for natural selection and the origin of species. The Grants’ achievement is monumental.”

“Peter and Rosemary Grant are members of a very small scientific tribe,” Princeton Alumni Weekly writer Joel Achenbach notes. They are “people who have seen evolution happen right before their eyes.” Evolution didn’t just “happen,” of course; there is a reason why their books are heavy in “scholarly apparatus.” “We need very precise numbers to know exactly what has happened to cut out any possibility for guesswork,” say Peter Grant.

“For the Grants,” observes Achenbach, “evolution isn’t a theoretical abstraction. It’s gritty and real and immediate and stunningly fast.”



The list of learned societies to which the Grants belong is very long, and they have won many honors along the way. In 2009 they were awarded the highly esteemed Kyoto Prize, presented by the Inamori Foundation of Japan to honor lifetime achievements in the basic science, advanced technology, and arts and philosophy. A comment by Peter Grant at the time reflects the couple’s pleasure in their collaboration: “it is a wonderful honor to be recognized in this way, and especially moving to know that we are the first husband-and-wife team to be given the award in the 25-year history of the Kyoto Prize.” As an old friend of the Grants reportedly observed, “the world will take much of what they do as Peter. Yet they really do something that transcends either one of them. That’s developed over a long period of time, probably to a greater point than even they themselves are aware.”

“Reading 40 Years of Evolution is like having an engaging conversation with two of the most prominent and charming field biologists of our time,” enthuses Harvard University Professor Hopi E. Hoekstra.

When asked about the success of their partnership, the Grants are characteristically modest. “It is founded on mutual respect,” they say. “I don’t think we’ve ever competed with each other,” Rosemary has said. “We come at things very differently. But it’s always had a synergistic effect.”

They are similarly successful at working with other scientists. “Respect for the differences may be the key to all successful collaborations,” they suggest. “Our collaborations with scientists at Harvard and at Upsala (since the book) have worked so well because all parties contributed different expertise.” Currently, the Grants say they are working “with colleagues who have the tools to analyze our demographic and genetic data. Our most recent paper, reporting discovery of a gene that controls beak shape development, was published in Nature just last week. We may return to Galápagos next year but have no immediate plans.”


It’s easy to wonder what it’s been like to divide each year between Princeton, where they arrived in 1985, and Daphne Major. Did they miss Conte’s pizza when they were in the field? Yearn for Daphne Major’s unspoiled beauty walking down Nassau Street? “Reentering society after a long time on an uninhabited island does take some adjustment,” they acknowledge. The journey back to Princeton included stops on Santa Cruz Island, Quito, and Miami airport. “Princeton is home”— they live a couple of miles from campus near Lake Carnegie—“so that does not require adjustment after the preceding experiences in transit,” they add. “Returning to Daphne Major is pure pleasure, and we do not pine for pizzas.”

The word “continuum” comes to mind with regard to Rosemary and Peter Grant’s work: the sense of it is everywhere in their new book, which is dedicated to “the next generation” and “succeeding ones,” and includes 34 pages of references to earlier research on which they build, while acknowledging the advent of new technologies (e.g., electrophoresis) over the years. They agree. “Continuum, yes; in the sense that we were dependent on our predecessors and hope that others will follow and take advantage of what we have discovered.”