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an online version of the magazine Fall 2007
Annals of Hopkins

Richter the Rat Man

Using ingenious tools like bicycle parts and special cages, this scientist showed the world how innate behavior in animals is tied to their bodily structure.




Curt Richter
> Through his close observation of animal behavior, Curt Richter launched the field of psychobiology.

WHEN 25-YEAR-OLD CURT RICHTER arrived at Johns Hopkins as a graduate student in 1919, there were few signs this squash-playing youth from Denver would one day achieve world fame as the father of the biological clock. At Harvard, where Richter had been an undergraduate, he had earned only one A, and didn’t have a clue about a career. But he’d read “snatches here and there” by the psychologist John B. Watson, and it was those meanderings that set him off on his life’s work. He decided to try his luck as a student in Watson’s psychobiology lab at the esteemed Phipps Psychiatric Clinic at the fledgling Johns Hopkins.

The atmosphere in that third-floor lab, Richter soon discovered, was charged. But what truly set his imagination afire was a cage with 12 rats that Watson presented him, along with the direction that he do nothing except produce “a good piece of research.” Richter fed the rodents some bread and milk, began watching them, and stumbled onto the question that would ignite his entire career. “They just jumped around the cage and climbed around for periods and then were quiet again,” he wrote in his first paper in 1922. “I couldn’t help but wonder what made them so active.”

That simple question and the straightforward technique he devised to study it would burgeon into other questions about the connection between animals’ innate behavior and their physiology. Over the next 63 years, Richter would study rats (both lab-bred and plucked from the streets of Baltimore), hamsters, squirrels, rabbits, monkeys, sloths, and even humans. Because he would evolve into a meticulous and curious researcher, he would publish more than 375 papers and lay the building blocks for the new field of psychobiology. And all of it, as Richter himself once reflected, because he set to work with a playful imagination.

When the youthful Richter took charge of his rat pack in 1919, few methods existed for describing animal behavior. So, he began creating the devices he’d need for his experiments. His first contraption—a special cage covered with a rubber membrane and sitting on tambours—was connected underneath by tubing to a small recording drum. Richter would feed the rats in the morning and observe them throughout the day. Meanwhile, as the animals scampered here and there, the recording drum noted every movement with a mark on the smoked paper of a graph-making instrument called a kymograph. A chronometer simultaneously registered the time on a chart. 

Within four weeks Richter had collected data demonstrating that rats behave in regularly occurring patterns. Determined to understand the nuances of these periodic phenomena, he began correlating the rats’ feeding times to their periods of activity and rest. When he found they became inactive after eating, he measured the length of the quiet periods. Then he showed that the rodents’ caloric intake remained consistent even when their drinking water was replaced with alcohol. Suddenly, a vast exploration of animal behavior had taken off. In 1922, when Watson left Hopkins, Adolph Meyer, the fabled head of psychiatry, handed the job as director of the psychobiology lab to the 28-year-old Richter, who had just completed his PhD.

Over the ensuing decades, unlike other scientists, Richter monitored the most intricate details of what rats did on their own—their ability to swim, to fight, and to select food with specific nutrients like calcium. One of the many contraptions he developed—this one from an umbrella and a sock—recorded every swallow of fluid the rodents took from a bottle. What would happen, he wanted to know, to each of these self-organizing behaviors if he altered one feature—the nutrients, say, or the daylight patterns, or even some aspect of the animal’s basic biology?

As Richter moved from experiment to experiment, he grew to love hashing over theories and experiments with colleagues. Timothy Moran, a Hopkins behavioral scientist whose 1970s studies of food ingestion overlapped with the indefatigable scientist’s at the end of his career, came to realize that Richter’s first five or six experiments had focused on issues he would continue to investigate for 50 years. “You’d be chatting with him,” Moran remembers, “and he’d say, ‘You know, I did something similar to that. Let’s see, it would have been 1942. Let me go over here.’ And he’d pull it out.”

Richter’s records were meticulous. Suite 318 in the Phipps Building where he worked was another story. Every surface was piled with paper, huge oak cabinets overflowed with charts, and portraits of decades’ worth of lab animals crowded the walls. During all the years he occupied the suite, Richter refused to allow it to be repaired or even repainted. “It wasn’t a mess, though,” declares Ardis O’Connor, now 91, who worked as his research assistant for 33 years. “He knew just where to find anything he wanted to put his hands on.”

Richter remained interested in periodic activities tied to animals’ biological clocks for the rest of his life, and in 1981 the work gained him a Nobel Prize nomination. He went on to demonstrate  how endocrine tissues and thyroid hormones affect sleep and sex cycles; he studied how removing tissue from the brain and other organs affects periodic behaviors; he sparked scientific interest around the world when he observed that removing the adrenal gland prompts a huge increase in salt ingestion. And finally, in the 1960s, before anyone else was looking at circadian rhythms, he localized the body’s regulation of sleep/wake cycles in the hypothalamus and kicked off a huge modern field of study.

Paul McHugh, who became head of the Department of Psychiatry in 1975, recalls that even then, when Richter was in his 80s, it was clear that he “was a genius in the tool room. He’d think about an idea,” McHugh says, “and then work out a piece of equipment using things like bicycle parts to demonstrate animal activity.”

Officially retired at 60, Richter remained vigorous well into the 1980s, still playing squash, still a regular in his lab. By then, though, his scientific work was winding down. “The money was drying up,” recalls O’Connor. Finally, with building renovations taking place around him, he practically had to be pried out, recounts a recent biography by Georgetown physiologist Jay Shulkin.

Richter had taken issue with the modern need to write grant proposals to gain support for research projects. Former colleague Jim Wirth still remembers him declaring that funding should be based on a scientist’s reputation and sincerity. “You don’t fund the work,” Richter would say, “because nobody knows what’s going to be important. You fund the man.”

Richter died at 94, in 1988. But his meticulous data and his expansive theories lived on, influencing new studies of everything from appetite to sleep patterns. Even today, 20 years after Richter’s death, Wirth, now a professor of psychiatry at Cornell, says “it’s hard to find a field in behavioral science that Curt hadn’t had his fingers in.”1

 Thinking Large
 A Place to Come Back to
 Sweet Relief
 Circling the Dome
 Medical Rounds
 Annals of Hopkins
Class Notes
 Where Are They Now?
 Learning Curve
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