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A Museum for the 21st Century

By Miyoko Chu

The Cornell University Museum of Vertebrates takes a dynamic new approach to research collections, using a combination of specimens, field observations, video footage, sound recordings, and DNA sequencing to study wildlife

When the Cornell Lab of Ornithology moved into its new home at the Imogene Powers Johnson Center for Birds and Biodiversity, more than a million fish, amphibians, reptiles, birds, and mammals moved in too. For decades, these specimens—belonging to the Cornell University Museum of Vertebrates—had languished in an old cinder-block building about half a mile from the Lab, isolated from the university and lacking such basic facilities as preparation rooms, teaching areas, and space for visiting researchers. The move to the Johnson Center has expanded the museum’s facilities in a central hub for research, a fitting place for a museum at the forefront of a dynamic new era in research collections.

Photo credit: Jon Reis
A Club-winged Manakin (above) makes an odd snapping sound with its wings during courtship. To find out how it does it, Kimberly Bostwick (below) studied numerous specimens, audio recordings, and high-speed videos.
Photo credit: Jon Reis

For most of the museum’s 125-year history, there was no such thing as an audio recorder, a video camcorder, or a DNA sequencing machine. These recent technologies have made it possible to preserve not just an animal’s body, but its voice, behaviors, and genetic code. The museum of vertebrates is now on the first floor of the new facility, strategically positioned alongside the Macaulay Library, the world’s first multimedia museum of animal behavior; the Bioacoustics Research Program, where engineers develop tools to collect and analyze animal sounds; and the Evolutionary Biology program with its state-of-the-art DNA laboratory. With these resources, researchers can use museum specimens, together with sound recordings, video footage, and DNA samples, to solve questions about the function and diversity of animals. How does a manakin make its love song? How does a catfish pinch and squawk? How did the rattlesnake get its rattle? The answer to these riddles cannot be found without traditional museum specimens, but these specimens alone are not enough to solve them fully.

The room housing the museum’s bird collection is filled with large rectangular metal cases lined up wall-to-wall. Altogether, they contain more than 38,000 study skins of birds. Kimberly Bostwick, curator of birds and mammals, studies a family of birds called the manakins. From the case marked Pipridae, she pulls out drawers filled with a dazzling assemblage of manakins from all over Central and South America. But the physical beauty of these birds tells only a portion of their story. In life, the males show off their brilliant finery to females, performing elaborate courtship dances to the rhythmic sounds they produce with their wings.

“What’s interesting about these birds is that they don’t all make wing sounds in the same way,” Bostwick says. Nobody knew that before Bostwick began measuring the wings, feathers, and bones of more than 500 specimens. When a manakin snaps its wings—producing a sound reminiscent of a drop of hot oil on a frying pan—the motion of the wings is just a blur to the human eye. But Bostwick found tremendous differences in the wing feathers, muscles, and bones of different manakin species, suggesting that the snap of a male’s wings is so fundamental to his success in winning a mate that it takes precedence over his powers of flight. “Manakins have heavier bones and bigger muscles in order to do these courtship displays, at the expense of being able to fly as well as other species,” says Bostwick. Additionally, her research hinted that there was more complexity and variation within that blur of wings than anyone had realized before.

There the story might have ended, except for a new invention: the portable high-speed video camera. “There was no way to take high-speed video in the field until recently,” Bostwick says. “And without high-speed video, we could never know how any bird makes sounds with its wings.” In Ecuador, Bostwick filmed manakins at 1,000 frames per second—a much higher speed than the 30 frames per second of a conventional video camcorder. The footage revealed that different manakin species use entirely different motions to produce similar-sounding snaps.

“Look at this White-collared Manakin,” Bostwick says, as she replays the video footage on her computer screen. “Here he is on his court—he’s chosen four or five twigs and cleaned a bare patch of ground underneath. When a female comes, he starts leaping among the twigs and making that snapping sound. There he is, jumping up. Now he’s whacking his wings above his back. It’s just interesting in principle that birds do this. But what’s really incredible is where the science comes in. He’s doing that as fast as hummingbirds beat their wings.” The footage showed that a Red-capped Manakin moves its wings just as quickly to produce a similar sounding snap by beating its wings against its sides. Furthermore, the Red-capped Manakin makes two additional kinds of snaps using completely different wing motions.

Bostwick is continuing her work on the anatomy and behavior of manakins, using the insights she gains to piece together the story of how they evolved the ability to make music with their wings and how different species are related to one another. Meanwhile, the video footage and sounds that she recorded have been deposited in the Macaulay Library so that other researchers will be able to study them well into the future, just as they can study the bones and muscles in the bird collection where some of Bostwick’s discoveries began.

Photo credit: Jon Reis
John Friel combines the study of museum specimens with sound and high-speed video to understand how catfishes evolved the ability to make sounds with their bones.

Just down the hall from the bird collection are four rooms containing 1.2 million fish specimens stored in vials, jars, and buckets on compact shelving that extends down the length of each room. What are these fish doing in one of the world’s largest centers for bird study? John Friel, curator of fishes, amphibians, and reptiles, can answer that question. He, like Bostwick, is interested in the evolution of animals that produce sound; his organisms just happen to have fins instead of wings.

Friel’s passion is studying the bones and musculature of fish, using anatomical clues to construct what biologists call evolutionary trees—branching diagrams that show how different species are related to one another. The more he studied the skeletons of catfish, the more he became intrigued with a group of bones called the pectoral girdle—the fin bones and associated structures.

“The densest bone in a catfish’s body is the pectoral spine,” says Friel, holding up a bone that resembles a delicate jawbone—long, slightly curved, and ridged with jagged teeth. This bone, adjacent to a catfish’s front fin rays and extending backward along the body, is unique among vertebrates and highly variable among different catfish species. Some pectoral spines look like a thorny branch, with teeth-like projections on all sides; others look like jawbones, combs, or smooth awls. Additionally, where the base of the spine meets the other bones of the pectoral girdle, there are intricate ridges and bumps that vary greatly among different kinds of catfish.

“The earliest fossil record of a catfish is from a spine like this, from the late Cretaceous, 65 million years ago,” Friel says. “They were obviously used for defense. By elevating these spines, they could effectively make themselves bigger. More primitive groups of catfish tend to do that—raise their spines without making noises.”

But if you scoop a catfish called the striped Raphael out of the water, you’ll hear an odd sound, as if someone is repeatedly running a finger up and down the teeth of a comb. Pick up a banjo catfish, and you’ll hear frog-like croaks in doublets: Uh uh. Uh uh. Uh uh. Still other catfish sound like chattering squirrels or someone’s knuckles rapping on a door. The species that make the most noises tend to be those that can harm a potential predator—especially by pinching, stabbing, or slashing with their pectoral spines or, in some cases, by releasing toxic chemicals from ruptured skin vesicles. No one knows for sure whether catfish squawk as a warning to predators or for some other reason. What is clear is that, as with manakins, the behavioral complexity of catfish is reflected in the marked variability of their sound-producing techniques and the shape of their instruments.

Catfish produce sounds as the base of the pectoral spine rubs against the other bones of the pectoral girdle. When Friel used high-speed video, in combination with sound analysis, he found that some catfish, such as the striped Raphaels, make sounds as they raise and lower their pectoral spines. Others produce sounds only when they raise their spines. Video footage at 500 frames per second revealed that striped Raphaels produced their sounds in a racheting start-and-stop motion that appears like a smooth sweep to the unaided eye. Sonograms show distinct sub-pulses that are produced by the friction of ridges on the surfaces of the bones. By studying the defensive behaviors of catfish, their sounds, and the intricacies of their bones, Friel ultimately hopes to reconstruct the evolution of sound production in catfishes, adding valuable new information to the catfish evolutionary tree.

Substitute a rattlesnake’s rattle for a catfish’s spine, and herpetologist Harry Greene is on a similar quest. Next door to Friel’s office, Greene stands between compact shelving filled top to bottom with snakes coiled up in jars of alcohol. As a teenager, long before he ever set foot at Cornell, he knew some of these very same specimens intimately. The Handbook of Snakes of the United States and Canada, published in 1957, by Albert and Anna Wright, was based on specimens in the collection. “Virtually every animal that was photographed for the book ended up as a specimen in the collection,” Greene says. “When I was a teenager, I devoured this book. I literally memorized it because it had such vivid field observations. When I read it, I imagined what it would be like if I could go to Texas and catch a coral snake.”

In fact, Greene, did go on to look for coral snakes and other venomous snakes, not only in Texas but around the world, and he used museum specimens to explore the diet of pit vipers and their relatives. Greene is now a professor in Cornell’s Department of Ecology and Evolutionary Biology and a faculty curator of the herpetological collection. He and his wife, Kelly Zamudio, also a herpetologist, faculty curator, and professor in the same department, are now studying the evolution of the rattle in rattlesnakes.

Although only rattlesnakes have rattles, all pit vipers have a small spine on their tail—a fact that Greene confirmed by looking at the tail tips of museum specimens from every genus and almost every pit viper species in the world. “That right there shows that the rattle didn’t just jump out of nowhere,” Greene says. “What we’re trying to do now is reconstruct the place, habitat, and body size of the earliest rattlesnakes. Once we do that, we can test different hypotheses about the origin of the rattle.”

Their strategy is to construct an evolutionary tree of rattlesnakes using natural history observations, morphological and dietary information from specimens, and DNA analyses. They’ll then be able to examine whether the rattles first arose in Great Plains rattlesnakes as a means of warning large ungulates—a widespread assumption that Greene believes is unlikely to be true based on the evidence he’s found. An alternative possibility is that the rattle evolved in the rocky habitats of the Southwest and Mexico, as a warning device against the snouts and paws of bears, ringtails, and coatis.

“More and more, anyone who collects animals for museum collections should not be satisfied simply with killing an organism and putting it in a jar,” Greene says. “We’re in a transition from the old days, when you just preserved a specimen, to the 21st-century way, which I call the ‘total specimen approach.’” That approach means collecting DNA samples, storing them, deciphering DNA sequences, and depositing the sequences in GenBank, a publicly accessible database maintained by the National Institutes of Health. It means archiving photographs, video footage, and audio recordings in the Lab’s Macaulay Library, where multimedia specimens will be globally accessible via the Internet. “The Johnson Center is the place where we’ll move the concept of the total specimen forward, and we’ll be doing it in a teaching context, for undergraduate and graduate students,” says Greene. “The museum is going to be much more effective now that it’s part of the Lab of Ornithology, because the Lab is such a conduit for vertebrate biology internationally.” Students and professional biologists alike will be able to pursue their research questions using physical and multimedia specimens, and a DNA laboratory, without ever leaving the building.

The value of having the collections accessible to students was made clear by one recent Cornell undergraduate, Amber Wright. She wondered whether environmental stresses from a local golf course might be affecting a small population of spotted salamanders. Working with Zamudio, Wright compared specimens that she collected from Bull Pasture Pond beside the golf course with specimens collected from the same pond by Albert and Anna Wright in the 1930s and 1940s, before the golf course existed. Changes in the symmetry of the spots on salamanders can be one sign of environmental and developmental stresses, so Zamudio and Wright used digital photographs to analyze whether the pattern of the salamanders’ spots had changed over the years. They found that the spots were significantly more asymmetrical now than they were 30 years ago at Bull Pasture Pond, while at the protected Ringwood Pond nearby, the symmetry of salamanders spots has remained unchanged.

The researchers who collected the museum’s specimens years ago couldn’t have known that a salamander’s spots might one day serve as a measurement of environmental degradation, that a manakin’s bones would lead to the first study showing how birds make sounds with their wings, or that a rattlesnake’s tissues would yield DNA sequences that could be used to reconstruct its evolutionary history. “Living with a museum in our midst is hugely rewarding intellectually,” says the Lab of Ornithology’s director, John Fitzpatrick. “It exposes us to whole sets of new questions.”

For permission to reprint all or part of this article, please contact Miyoko Chu, editor, Cornell Lab of Ornithology, 159 Sapsucker Woods Rd., Ithaca, New York. Phone (607) 254-2451. Email mcc37@cornell.edu