Whales in the Cliff Face
An exposed prehistoric seafloor is a hotspot for ancient whale remains, and now an international team is helping unravel their mysteries.
Article body copy
Stephen Suntok pushes through a tangle of blackberry bushes. It’s a gray July morning on Vancouver Island in British Columbia, and the smell of smoke from a wildfire to the north mixes with the briny sea breeze. Suntok looks up for a moment, gazing at the pale sky, then picks his way down a beach access clogged with tree trunks. Along the shore, the tide has retreated, revealing an expanse of boulders coated in blankets of slick, verdant algae. Seagulls wheel overhead as the waters of nearby Muir Creek flow into the Salish Sea.
Suntok works as a criminal defense lawyer in Victoria, British Columbia’s capital city, but he spends much of his spare time in the service of science, collecting rare fossils that he donates to museums. For at least a decade and a half, he has searched shores and river gorges across Vancouver Island, collecting a wide variety of fossilized specimens—including the dental plate of a previously unknown fish, Canadodus suntoki, which paleontologists named after him, and a rare species of crab from a beach near Campbell River, where the species was once plentiful. But of the many sites he checks regularly, few match the rock formations along Muir Creek beach when it comes to vertebrate fossils. In some spots, the sandstone cliffs and intertidal boulders are studded with fossil shells and bits of fossilized bone that date to more than 23 million years ago. It’s in this ancient boneyard that Suntok has made some of his most intriguing discoveries—the fragmentary remains of ancient whales that lived and died in the ocean here tens of millions of years ago.
This morning, Suntok has agreed to take me along for a visit to this fossil site. In the distance, lush green forest spills over the tops of the cliffs that border the beach. As we slowly approach the site, weaving along the slippery beach rocks, Suntok begins scanning every boulder we pass for fossils. Up close, the curved, overhung cliff face looks barren and austere, like something from a sci-fi movie set on another planet. Each layer of stratigraphy is a stark stripe of brown, beige, or gray, and some are flecked with white shells. These rocks date to an epoch known as the Oligocene, which stretched from 33.9 to 23 million years ago. It was a time of global cooling, when grasslands expanded on land, and mammals such as horses, camels, and primates began spreading out.
Suntok slides a pair of reading glasses onto his nose, then hunches down and rolls onto his back to get a better look at a low shelf near the base of the cliff. Fossils can sometimes be extremely difficult to spot, he explains. The first vertebrate fossils he found at Muir Creek belonged to an extinct species of Oligocene whale, but initially, all he could see on the surface of the rock was a tiny half-moon-shaped irregularity. It was the tip of a fossilized bone. Subsequent excavation revealed three fossil vertebrae locked in the rock. Since then, Suntok has scoured this beach dozens of times. It always looks different, he says, because the waves chip away at the cliffs, revealing new surfaces to check.
At the base of the cliff, Suntok continues poring over the low shelf, checking small irregularities in the rock. Soon, he spots a sliver of fossilized bone—possibly a small fragment of a rib from an ancient marine mammal. But Suntok opts to leave it in place. It’s just a scrap and removing it without the right tools would result in damage. He is only carrying a hammer and chisel today. In British Columbia, fossils found on Crown land are protected as heritage objects under the Land Act, and fossil hunters are required to report major finds so that skilled researchers can take them out with the proper tools and methods. But it’s good practice to report fossils whenever they are found.
Suntok is patient when it comes to fossil hunting. He has seen for himself how precious these pieces of fossilized bone can be for the researchers who study ancient whales and other marine life. “Everything I’ve found is just a rock … until a paleontologist who knows what they’re doing studies this thing and describes it and puts flesh on the bone,” he says. “Before that, it’s just a curiosity in my cabinet.” Each whale fossil, after all, is a potential clue to the long and complex story of cetaceans, and to the dramatic transformations they underwent over millions of years. Moreover, the study of ancient whales has taken on new relevance in an era of rapid climate change. A better understanding of the remarkable evolution of cetaceans could assist researchers and conservationists alike in protecting whales in the future, as these leviathans are confronted with the increasingly harsh realities of a world dominated by humans.
Whales are among the largest animals to ever exist on Earth, with some adult blue whales reaching 180 tonnes, nearly 21 times the weight of a Tyrannosaurus rex. And the long history of whales, which spans more than 50 million years, is chock-full of surprises. The earliest whales lived near water—but not in it—and they looked very different from the whales we know today. Pakicetus, for example, was a wolf-sized animal with four legs, a long snout, and a big tail. It hunted small prey along the coastal margins of Pakistan some 50 million years ago. But what links Pakicetus and the other early whales to modern cetaceans is a distinctive anatomical feature they all share: a bulbous structure in their ears known as an involucrum. This ancient structure may assist today’s whales and dolphins in hearing underwater. Early whales also had distinctive double-pulley ankle bones seen only in even-toed hoofed mammals, like camels and cows, which are now understood to be whales’ closest relatives.
As cetaceans evolved, forelimbs became flippers, nostrils shifted back to become blowholes, and legs eventually disappeared. It took whales about 10 million years to transition from land to sea, and they may have done so for a variety of reasons, which include escaping predation on land and capitalizing on abundant marine prey. But once whales were completely aquatic, they spent the next 40 million years adapting fully to life in the ocean. For much of this time, most cetaceans were little bigger than a humpback whale. Then, beginning around 4.5 million years ago, whales underwent another remarkable transformation. Many began bulking up dramatically, eventually reaching their current extreme sizes. That allowed them to bump up the amount of prey they consumed in one gulp, swim vast distances to reach places with abundant food sources, and fight off most marine predators.
That’s the basic, broad trajectory, but huge gaps remain in our knowledge of whales—including how baleen evolved in some species. And that’s where whale fossils come in. Fossil bones preserve enormous amounts of information, and whale fossils from the Oligocene era are particularly valuable, given the many changes that cetaceans went through at that time. The trouble is that marine fossils from that era are exceedingly difficult to find in most parts of the world. Sea levels during the Oligocene were much lower than today, so fossilized marine life from that time tends to lie deep beneath the ocean—beyond the reach of paleontologists.
But in a few parts of the world, scientists have discovered rock formations on land that are littered with these rare Oligocene marine fossils. The Pacific Northwest is one such place. Sometimes, when whales and other marine animals died in the shallow oceans of the Oligocene, their skeletons were buried by sediment on the seafloor. Over time, the sediment hardened into layers of rock, and the bones sandwiched between these layers slowly petrified, becoming fossils. Eventually, major geological processes pushed these Oligocene layers above sea level in the Pacific Northwest. At localities like Muir Creek, strong waves and heavy winter rains batter the cliff faces, eroding the rock and revealing the fossils within.
“It’s basically kind of a combination of the right conditions 25 million years ago, and then the right conditions today,” says Victoria Arbour, the curator of paleontology at the Royal BC Museum (RBCM) in Victoria. She and a recent University of Victoria graduate, Elizabeth Rohlicek, have been trying to identify a collection of cetacean fossils from Muir Creek and nearby Kirby Creek, and piece together the stories they tell about whales in the Pacific long ago.
On a midsummer morning in a darkened gallery at the RBCM, Arbour and Rohlicek lead the way through a new exhibit on killer whales. Whale calls echo and blue lights swirl across the killer whale models and Free Willy memorabilia, as Arbour, on maternity leave, pushes a stroller holding her newborn son, Oswald, or Ozzy for short. A leading expert on armored dinosaurs, Arbour clearly loves all things paleontology. Her Twitter feed brims with artists’ reconstructions of dinosaurs and other extinct animals, and she is fond of fossil-themed fashion. Today, she’s sporting a collared shirt teeming with tiny dinosaurs. Behind her, Rohlicek, the 23-year-old former student she’s mentoring, flashes a bright smile. Animated and self-assured, Rohlicek lights up when she gushes about ancient whales.
Midway through the exhibit, the museum’s collections manager joins us. He’s pushing a cart stacked with some of the fossils found at Muir Creek. Most of these specimens, Rohlicek explains, are marked with information about where they were found and by whom. The bones and fragments—ranging from complete vertebrae and rib bones to a piece of skull—were collected by fossil finders, including Suntok, over the past 60 years. All of the specimens, however, were sitting in storage, waiting to be identified and studied when Arbour and Rohlicek began their research project in the fall of 2020.
It’s not uncommon for fossils to sit in museum drawers for decades before they are investigated, says Arbour, who joined the RBCM in 2018. Sometimes, there’s insufficient people power at museums to study them, and other times, it’s a lack of people with the right research background for a project. But often curators must wait until a collection holds enough specimens to tell a story. That’s why paleontologists urge fossil hunters to donate their finds to a university or museum where they can be preserved for future studies. A single rib from Muir Creek wouldn’t have prompted a research project, Arbour explains, but by the time Rohlicek, then an undergraduate student, joined her lab in early 2020, the collection had accumulated enough specimens to ensure an interesting takeaway.
Rohlicek was majoring in biology and earth and ocean sciences at the time but had become enamored with paleobiology—a branch of paleontology that investigates the evolution of fossil species and how they fit into ancient ecosystems. She was considering a career in paleobiology and contacted Arbour to hear how women fare in this field, which is still dominated by men. With Arbour’s encouragement, she began volunteering in the RBCM’s paleontology lab. And after the museum was forced to close its doors in 2020 due to the pandemic, Arbour invited her to assist with a study of the Muir Creek fossil collection. Rohlicek leaped at the opportunity.
Access to the museum labs was restricted, however. So, starting in the fall, the two women met at the museum every Wednesday evening after closing and rolled a mobile lab—a plastic cart stocked with marine fossils, measuring tapes, and sketch pads—into the public Natural History Gallery. Next to a life-sized mammoth sculpture known affectionately as Woolly, they got to work, poring over the specimens by lamplight as the ambient nature sounds from the exhibit played on a loop—the soundtrack to their research.
For Rohlicek, analyzing all those unknown marine fossils with Arbour in such a surreal environment was both intimidating and exciting. “I had these fossils that no one had ever looked at, and that had never been published about,” she says, still marveling at the experience. To gather vital data, the pair examined each fossil carefully, photographing, sketching, and measuring it. Then they compared each to similar-looking bones from known species. In this way, they identified the body parts and determined that the fossils belonged to whales that roamed the world’s seas during the Oligocene.
This was a time of major tectonic activity. When South America and Australia drifted north, splitting away from Antarctica, a path was cleared for a new circumpolar current. Global temperatures dropped, sea levels fell, and the new current caused widespread upwelling—a process that pushes nutrients from the deep up to the surface, resulting in localized plankton blooms. And this may have helped spur the evolution of baleen whales—called mysticetes, a name derived from Greek words meaning “mustache whale”—as they began to swap their teeth for long keratinous plates and gradually shift from hunting for meals to filter-feeding. At the same time, echolocation was developing among toothed whales, and this ability to detect distant things with the aid of reflected sound waves, allowed them to navigate in deep, dark waters and hunt the prey that flourished there. This combination of diversification and tough-to-find fossils, says Robert Boessenecker, a whale paleontologist at the College of Charleston in South Carolina, “is what makes the Oligocene so damn interesting.”
For Rohlicek, the next step was to gather research on the cetacean species thought to have lived in the northeast Pacific during the Oligocene. She soon discovered that the Pacific Ocean was once a terrifying place where many predators lurked. One of the most nightmarish was an ancient whale with a huge, eel-like body, serrated teeth, and tiny hind limbs that couldn’t have supported its enormous body. Its name was Basilosaurus, meaning “king lizard.” Originally classified as a reptile, Basilosaurus dwarfed the other early whales. It measured more than 15 meters from snout to tail—about the length of a standard bowling lane—and evidence suggests that it ate smaller cetaceans, as some killer whales do today. Basilosaurus is thought to have gone extinct before the beginning of the Oligocene, but some may have survived in certain areas after that, Rohlicek says. “It’s not like they all just died off right on the first Tuesday of the month,” she explains.
As Rohlicek continued delving into her cetacean research, Arbour began contacting paleontologists who specialize in whale evolution. She knew that she and Rohlicek would need assistance in identifying the species represented in the Muir Creek collection, and after years of rubbing shoulders with other paleontologists, Arbour knew who to ask. “People sometimes think science is very siloed and competitive,” she says, “and for sure that also happens, but it’s not all like that.” Often, she notes, getting help is as simple as calling up a colleague and saying, “Hello, Friend-who-knows-random-whale-vertebrae, what is this?” So that’s exactly what she did.
One of those colleagues was Nick Pyenson, the curator of fossil marine mammals at the Smithsonian Institution in Washington, DC. Pyenson is a vertebrate paleontologist who has spent many years studying whales, and he was willing and able to help.
One of Suntok’s fossil finds, a partial scapula with fine fractures, posed a unique challenge, says Rohlicek. After extracting it from the rock, Suntok set the fossil in plaster to prevent damage. The casing protected the specimen well, but it permanently hid one side, making the fossil difficult to identify. But Suntok’s field notes contained a vital clue: near the shoulder-blade fragment, the lawyer found a fossilized atlas—the vertebra from the base of a whale’s skull. And when Rohlicek and Arbour showed the specimens to Pyenson on a video call, he immediately recognized the small bumps on the outer edge of the fossilized atlas. They were a telltale skeletal trait of ancient river dolphins. Rohlicek and Arbour were delighted. The close proximity of the two fossils at Muir Creek suggested they may have come from the same individual.
River dolphins are cetaceans, and the earliest species seem to have thrived in salt water before they eventually shifted into river habitats. Today, river dolphins are found in the warm waters of South America as well as various river systems in Asia, but during the Oligocene, some species clearly inhabited the cold waters of the northeast Pacific.
As the research progressed, Arbour and Rohlicek identified two additional groups of cetaceans among the fossil bones in the Muir Creek collection: a Basilosaurus and a possible member of the genus Aetiocetus, which includes small baleen whales that had yet to lose their teeth. A pair of mystery vertebrae still partially embedded in rock—and a few other backbones in the collection—seemed to be of the same general size and shape as those thought to belong to aetiocetids and described in publications by other researchers. But that was just a hypothesis. Paleontologists had studied the distinctive skulls of aetiocetids but they had yet to fully describe other parts of the skeleton, and Rohlicek and Arbour didn’t have a skull to guide them.
But a fossil whale skeleton sitting nearly 4,000 kilometers away in Pyenson’s lab in Washington, DC, held hope for clinching the identification of the mystery vertebrae.
The Smithsonian Institution is home to the largest collection of whale fossils in the world. Examples of nearly every lineage of whale can be found at the Smithsonian’s National Museum of Natural History (NMNH) in Washington, DC, or in the museum’s storage facility in nearby Maryland.
“The Smithsonian preserves how the world once was,” Pyenson says on a balmy October morning, after rushing in a few minutes late for our appointment at the NMNH. The blue-eyed paleontologist has taken part in scientific expeditions to every continent on Earth, including Antarctica, but today, attired in dress shoes and a collared shirt despite the stifling humidity, he would blend in with many of the city’s politicians and executives. Indeed, on a crowded sidewalk, Washington’s elite would have no idea they’re standing next to one of the leading authorities on whale evolution.
Pyenson leads the way through the exhibits and down to the laboratories and offices. As we cross the Sant Ocean Hall, he pauses under a cast of an early whale with four legs, Maiacetus, which hangs from the ceiling. As I gaze at the doglike skeleton in wonder, he points out a second huge cetacean suspended nearby: Basilosaurus, the giant eel-shaped whale that Rohlicek identified in the Muir Creek collection.
The 19th-century founders of natural history museums could not have imagined the amount of damage that humans would wreak on the world’s ecosystems, and all that would be lost because of this, Pyenson says. They merely collected everything they could. Over the years, curators at the Smithsonian’s 11 museums have added about 145 million specimens and other objects to the collection—from fossils and shells to modern art and space shuttles. As Pyenson peers over his mask—which is emblazoned with a graphic visualizing the global average temperature rise over the last 150 years—he says we need such records of past worlds. Museums not only protect the past; they can help us navigate the challenges of the present and future. “Sea level change, ocean acidification, and habitat loss—those are all features that we see through geologic time,” he says, “and we’re living through them in human lifetimes.” Learning how ancient whales adapted in the past can provide context for how they’ll fare in the future. “The story of what will happen has been written before,” he adds.
In the East Wing, one floor below the museum’s spacious public halls, Pyenson ducks into the dimly lit fossil marine mammal collections. It’s a labyrinth of wooden cabinets that date back more than a century and modern industrial shelving units packed with fossils, boulders, and protective plaster cases. He passes a large Triceratops skull affixed to a wooden platform before turning down row 25 and opening the first cabinet. The drawers inside are lined with ribs, teeth, skulls, and other fossilized fragments—remnants of ancient whales.
Stored in these seemingly endless rows are some of the Smithsonian’s nearly 20,000 marine mammal fossils, Pyenson says, his voice almost drowned out by the ventilation system. From a nearby drawer, he pulls out the honey-colored cast of a foot that belonged to a 47-million-year-old whale called Rodhocetus. Like otters, beavers, and other semiaquatic mammals, this whale may have had webbed feet, he explains. It’s an intriguing mental image, but such specimens are much more than curiosities. At the Smithsonian, scientists can compare and contrast cetacean fossils from different geological eras and climatic periods, gaining new insights into the adaptability and resilience of whales.
Another floor down is the vertebrate paleontology lab. Laid out on tables in the middle of the room are two fossilized skeletons of small, toothed baleen whales from a site in Pacific Rim National Park Reserve in British Columbia. They likely hold the key to officially identifying several vertebrae from Muir Creek. In 2012, armed with a rock saw and a permit from Parks Canada, Pyenson excavated these two skeletons and brought them back to the Smithsonian, where he and a large team began exposing them from the surrounding rock matrix. Today, the skeletons are nearly ready to be studied, and Pyenson is now certain that one is an aetiocetid. The other, he explained later by email, “may belong to that family or possibly to another group of early baleen [whales] with teeth.”
But what’s generating real buzz is that both specimens have backbones associated with well-preserved skulls. “Now we have a lot more of the puzzle,” Pyenson explains, as he lifts vertebrae and sharp teeth. “That gives you identity.”
By discussing the Smithsonian’s aetiocetid specimen with Pyenson, Rohlicek was able to confirm her conclusion that the mystery vertebrae from Muir Creek also belonged to an aetiocetid. It was a very rewarding example of international sleuthing. The newly exposed skeleton at the Smithsonian gives you security in connecting aetiocetid skulls with vertebrae of this size and shape, Pyenson says.
But piecing together the existing fossil record is only part of the work for Pyenson and other whale paleontologists. Cetaceans, he explains, have a “deep evolutionary history that goes back through geologic time.” By studying and analyzing this immense record of change, Pyenson hopes to deepen our understanding of these animals, “not just for the ones that are extinct but for the ones that are still alongside us.” It’s a history laden with information, and though some chapters are still missing, paleontologists hope that it may offer clues as to how the world’s whales will fare in the age of rapid climate change.
In his 2018 book, Spying on Whales, Pyenson assembles some of these clues. He notes, for example, that whales at the far extremes of body size may have a very tough go in the future. The giants of the cetacean world, such as the blue and fin whales, may have bulked up in order to migrate long distances and become more efficient feeders, but their immense size now puts them at greater risk of ship strikes and becoming entangled in fishing gear. Other whales that became highly specialized in their diets, such as certain killer whale populations that feed exclusively on salmon, could be wiped out in places like the northeast Pacific if their food source succumbs to rising water temperatures.
So can whales adapt quickly enough to survive the Anthropocene? Pyenson says it remains to be seen. Cetaceans have certainly proved themselves to be remarkably resilient over the past 50 million years. Still, some species may not survive the 21st century, says Pyenson, “while others will probably outlive us.”
On a warm July day, dog walkers meander contentedly across the sand at Muir Creek, hurling sticks for their eager companions. Near the beach access, a young family sets out for an afternoon on the sand, chatting excitedly and searching the tall grass for harmless local snakes. For them, and for most people who come here, Muir Creek is a day trip, a getaway, a welcome reprieve from the daily nine-to-five. But for fossil enthusiasts and the paleontologists who study their finds, the beach offers something rare and important: an opportunity to peek more than 23 million years into the past. The cliffs at Muir Creek are strewn with ancient vestiges of aquatic life, and to Rohlicek, this beach “could be a huge stepping stone in understanding whale evolution in the northeast Pacific.”
Much has changed since the Oligocene, but there’s one thing that hasn’t. The waters off Vancouver Island are still home to diverse populations of whales—from humpbacks to killer whales. But without major conservation efforts, without strong measures to slow the pace of climate change, some of these living whales could easily go the way of Basilosaurus and other extinct cetaceans. And as paleobiologists know better than nearly anyone, once a species is lost, it’s gone forever. It becomes just another fossil, “just another backbone in the cliff face,” Rohlicek says.