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Rachel Ellison

Of Minds and Macaques

Long before arriving at Willamette University, Rachel Ellison ’05 realized she wanted to work with animals.

During high school she volunteered at veterinary clinics, and after graduation she spent a summer on the coast of Athens, Greece, rescuing and rehabbing sea turtles. But it was during her internship at the Oregon National Primate Research Center in Beaverton, while earning her degree, that Ellison combined her love for animals with her interest in the brain and behavior. With the help of Sue Koger, psychology professor, Ellison designed her own major in neuroscience.

“One of my first jobs was to take the older monkeys up to OHSU for MRI imaging,” Ellison says. “As they age, monkeys’ brains change just like humans’, and you can see it on MRI.”

The experience helped her establish a methodology for analyzing the monkeys’ brain volume. “Previously there was no set way to reliably analyze monkey brains, partly because they are about the size of a human fist,” Ellison explains. “Information about the smaller structures in a monkey brain is compressed in a magnetic resonance image (MRI), averaging data from overlapping brain structures into a single pixel and making it harder to get detailed results.”

“There is no replacement for the behavioral research that can be done on monkeys. We can control many environmental factors and learn much about various behaviors that are surprisingly human-like.”

Ellison compared the pros and cons of various existing methods of analysis to help researchers account for the averaging. Her subsequent paper on the topic was so good, her advisors at Willamette and the Primate Center urged her to present her work at the Ninth International Congress for Stereology and Image Analysis in Zakopane, Poland, in May 2005. She had to miss her own graduation ceremony to attend, but for Ellison, that was a small price to pay. “It was an honor just to attend the conference,” she says, playing down her third-place finish against a field of doctoral candidates. “It was the most concentrated learning experience of my life.”

Not only did she gain valuable experience, she came home with a certifi- cate, a digital camera and a job offer from the Primate Center.

Actually, Ellison has two jobs at the center—research assistant and veterinary research health technician—and her responsibilities range from providing basic medical care for the animals to conducting scientific behavioral studies.


Today, Ellison continues to assist with aging research. She is also involved in a variety of behavioral studies, including mating behavior, dominance, and tricotillomania, a condition occurring in humans and monkeys that is characterized by hair pulling.

Whatever the task at hand, Ellison dresses for the occasion, wearing hospital scrubs, a protective gown, face shield and padded gloves. “At the Primate Center, we work with rhesus macaque monkeys, and they are definitely not domesticated,” she says. “They are not predictable, so we need to wear extensive gear that protects both humans and monkeys. Even if you have known and worked closely with one of these monkeys for years, you wear the gear to protect both yourself and the monkey from transmitting disease.”

When it comes to observation, Ellison trades her pathogen-protective clothing for lab coat, clipboard and a bag of monkey treats and heads toward the back of the Primate Center’s 300-acre compound, climbing the steep wooden steps to a covered observation platform overlooking a half dozen grassy corrals.

“Monkey behavior in the corrals is pretty close to their natural behavior in the wild,” Ellison explains. “There is no replacement for the behavioral research that can be done on monkeys. We can control many environmental factors and learn much about various behaviors that are surprisingly human-like.”

Ellison is aware of the controversy surrounding animal research, and she has answers for those who ask. “What most people don’t take into account is that the benefits extend beyond human concerns and go back to benefiting the animals themselves. Our findings are used to improve the quality of their lives too.”

Controversy aside, Ellison knows she will continue a career working with animals. She’s headed to either veterinary school or a graduate program in wildlife field research next fall.


Monkey Myths

Rachel Ellison says she finds herself answering the same questions—some silly, some serious—time and again. Here are her answers to the five most frequently asked:

  1. Only one-tenth of one percent of all scientific research is conducted on monkeys. The other 99.9 percent is done using mice or other laboratory animals.
  2. Of the research being conducted on primates, the vast majority is done on rhesus macaques—not on chimpanzees, gorillas or other higher-order primates. Chimps, gorillas, bonobos and orangutans are known as apes; monkeys are a separate taxonomic grouping.
  3. Of the nearly 4,000 non-human primates at the OHSU Primate Center, almost 93 percent are rhesus macaques. The rest are Japanese macaques, cynamologous macaques, baboons and vervets.
  4. Monkeys do not make good pets. They cannot be domesticated, and keeping a monkey in a human-centered environment interferes with their normal behavior.
  5. Monkeys typically do not “fling” their droppings—unless they’re doing a little hurried housekeeping.