The Frogman Who Found Frogs

When I was growing up in Dortmund, in Germany's industrial heartland, a career chasing frogs in the Caribbean was never on my mind. From the age of eight I collected exotic travel catalogs, and I owned a lot of books about nature. It took a few detours, most of them underwater, before those two interests came together.

Pearson College and the sea

In 1982 a scholarship from the Studienstiftung des Deutschen Volkes, the German national academic foundation, took me to Lester B. Pearson College of the Pacific in Victoria, British Columbia. Pearson is one of the United World Colleges, which bring students from all over the world to live and study together. I trained as a scuba diving instructor there and led the college's diving service. Our job included helping to survey the marine life around the Race Rocks Ecological Reserve, a cluster of small islets off Victoria.

Then the famous underwater explorer Joseph MacInnis came to give a lecture. In 1974 he had been the first person to dive beneath the North Pole, leading the Arctic IV Expedition. Afterwards I went up and asked whether I could join him on a dive in the Arctic. It was a bold question for a teenager, but he took it seriously. With his help, and with Dr. John Green of Memorial University of Newfoundland making the arrangements, I joined an expedition to Hudson Bay as a research assistant.

The same year brought a very different adventure. In June 1983 my Pearson friend Pauline Craig, who lived in Whitehorse, and I set off down the Yukon River. Her father dropped us off at Lake Laberge with the family canoe. We crossed the lake and paddled some 700 kilometers downriver to Dawson City. Along the way we took a short detour to Stepping Stone, a camp of the Third Order of St. Francis on the Pelly River. They sent a motorboat to tow us a little way up the Pelly to reach them.

That summer on the Digges Islands I worked mostly on Black Guillemots, a kind of seabird, with David K. Cairns, who was then doing his PhD at Carleton University and is now with Canada's Department of Fisheries and Oceans. I also got my Arctic dives: a couple of them with John Green, in water at −1.5 °C.

Those months in the North are when my love of science and exploration really caught fire. I received my International Baccalaureate from Pearson in 1984. Before university I spent a year as an intern teaching high-school biology at Brent International School in Baguio City, in the mountains of the Philippines.

A marine biologist at McGill

I enrolled in marine biology at McGill University in Montréal. As an undergraduate I also traveled whenever I could, on a shoestring budget: to Hong Kong, Macau, Japan, Mexico, Kenya, and Tanzania.

My first scientific paper came out of the tropics, but not from the sea. In May 1986 I was part of a McGill field course at the Bellairs Research Institute in Barbados. Over nearly three weeks we measured branches and weighed the fruit on 22 species of Barbadian trees and shrubs, from wild and garden plants to orchard trees. With one simple formula, based on how thick a branch is and how heavy each fruit is, we could predict how much fruit a branch carried. It explained 89 percent of the variation we measured. As plants get bigger, their fruit makes up a growing share compared with their leaves and twigs. Put another way, bigger plants invest proportionally more in reproduction. The paper, led by the McGill ecologist Robert Peters, appeared in the journal Oecologia in 1988, with eight authors.

In the summer of 1987 I went back to Barbados as an undergraduate marine biology research assistant. Those two stays got me hooked on the Caribbean. I fell for the balmy weather, the incredible people, and the phenomenal biodiversity, though at the time I was only thinking about the ocean.

A sponge with the smallest needles

My second paper was about a sponge. Because I was in a marine biology program, I asked Henry Reiswig of McGill's Redpath Museum for an independent research project. He searched through a set of "orphaned" vials on a shelf, handed me one, and said, "Here, figure out what this is."

Henry had collected the sample in 1984: a thin, grayish-yellow sponge from a tidal pool 23 m inside a sea cave on Edward King Island, in Barkley Sound on the west coast of Vancouver Island. Sponges are supported by a skeleton of tiny glassy needles called spicules. Over one semester I described the sponge's structure and worked on its spicules, and wrote a report. When I presented it, Henry asked, "What are these really tiny spicules? This is new, and it might be a new species."

So I spent a second semester on the spicules, and we looked at them under the electron microscope. They were only about 4 thousandths of a millimeter long and covered in minute spines, the smallest sponge spicules known. Each one forms inside a single cell, and twenty to fifty of them are packed into each of those cells. We suggested they might help defend the sponge against grazing snails. Henry wrote the paper, and in 1989 we named the sponge Mycale bamfieldense, after the village of Bamfield and its marine laboratory, the nearest human settlement to where it was found.

Henry kept turning up in my career after that. When I began measuring frogs, I did it on his digitizing tablet. In one paper I thanked him for his patience, since his equipment "was occupied for hours with frog carcasses."

Converted at the Redpath

The turn came in the fall of 1987, in Biol 327, a course taught by David Green at the Redpath Museum, McGill's grand old natural history museum. It was only the second year David had taught it, and there were just nine of us. David studies frogs. His lab technician at the time was Tim Sharbel, who later became my roommate in graduate school. Today Tim is a professor at the University of Saskatchewan and one of the world's foremost plant geneticists.

Inspired by David, I found my direction, and when he asked me what I wanted to do for a graduate research project, the answer seemed obvious. As I later put it: "David's a frog guy and I like the Caribbean. . . . Does 2 + 2 = 4?"

I did my fact-finding in the library first, and I was impressed by how much work had already been done on Caribbean frogs. Then I began to realize how much was still left to do.

Over New Year's 1988/89, my cousin Helmut Schwarten and I spent three weeks on a four-island tour of Barbados, Grenada, St. Vincent and St. Lucia, collecting the whistling frog Eleutherodactylus johnstonei. I came home with about 300 specimens. Half of them flew back to Canada with me on the jumpseat in the cockpit of a Wardair Boeing 747, much to the crew's amusement. I can recommend flying with live frogs to anyone who wants plenty of conversation on a business trip.

Some of those frogs weren't E. johnstonei at all, but a form of a Trinidad frog that looked quite different in life. After talking it over with David, I decided to write a grant proposal and take on the classification and history of all the Eastern Caribbean whistling frogs as a PhD project. When the grant came through, several more trips to the Caribbean were assured.

Spotted frogs and a fossil

Throughout my years as a graduate student at McGill, from 1988 to 1993, we helped David with his various projects. For my PhD I had developed ways of comparing frogs by their measurements, so I helped with David's work on the spotted frogs of western North America. My statistics and graphs brought out differences in body shape among populations, and those were useful in forming hypotheses about which populations were separate species. That work went into two papers with David, Tim, and others, in 1996 and 1997. The second one showed that what had been called a single spotted frog in fact included cryptic species.

The same statistics got me onto a paper about a fossil, with Michael Caldwell and Bob Carroll. Their animal, Carsosaurus marchesetti, was a relative of the mosasaurs, the great sea lizards. We used the numbers to ask whether it had been more likely fully aquatic, like a mosasaur, or fully terrestrial, like a monitor lizard. It came out in between, so it was probably a beach-dweller that could forage in the water. The paper appeared in the Journal of Vertebrate Paleontology in 1995.

Why it matters

Looking back, none of it was planned. A lecture, one bold question after it, a vial from a shelf, a field course, and a teacher who happened to study frogs added up to a life's work. I have tried to pass that on. Students learn best when they get their hands wet in real research, and the right question, asked at the right moment, can change everything.