Monday, January 19, 2015

The Pepperwood Creek Affair

Dr.Victor C. Twitty (left) and academic colleagues, 1955, Amherst
Photograph from Esther M. Zimmer Lederberg memorial website   
In 1953 through a fishing buddy, Dr. Victor C. Twitty was introduced to a rancher who owned fourteen-thousand acres in rural Sonoma County. Twitty asked the rancher if he could conduct newt research there and the rancher agreed even providing a small house near an amphibian-rich stream. "Thus the Pepperwood Creek Affair was born" and Twitty established a newt field research center far away in miles and in focus from his academic and administrative responsibilities at Stanford University.

At Pepperwood Creek through the 1950s and 1960s, Dr. Twitty and students conducted experiments on the homing ability of red-bellied newts at a time when not much was known about the breeding behavior of salamanders, and nothing of the western newt species. This research was initially a side experiment to gain background information on the behavior they should expect from the hybrid larvae they were artificially creating in the field lab by crossing eggs and sperm of California newts, rough-skinned newts and red-bellied newts, and then releasing them into Pepperwood Creek. Since the hybrids would take four to six years to reach breeding age, the researchers started capturing native red-bellied newts in a one-and-a-half-mile section of Pepperwood Creek (the 'experimental stretch'),  and with a mark-and-release strategy, monitored their return in subsequent breeding seasons.

To mark the research subjects, Dr. Twitty and his students snipped off toes of the study newts to designate a unique four-digit identification number for each individual. Originally, they removed an entire leg on each study animal, but then discovered that although the newts could navigate land and water and even breed with three legs, they regenerated their lost limbs within a year and then it was difficult to distinguish the amputated study newts from the original population. Although the clipped toes also regenerated, they remained notably smaller than the other toes for several years and their toe-clipping technique would allow the researchers to code over 15,000 individual newts.

Ann, a favorite hiking buddy, ponders the loyalty of red-bellied newts to their natal stream.   
The Twitty team discovered that most red-bellied newts returned to within 50 yards of the same stream section from which they had been captured in a previous breeding season. For example, in 1960 they collected and marked 564 male red-bellied newts in Pepperwood Creek and released them one mile downstream. By 1965, sixty-four percent of those had been recaptured "the great majority in precisely the part of the stream from which they had been displaced . . . A few of the newts failed to make the homing journey, and instead adopted, at least temporarily, the part of the stream where they were released."

Twitty described the constant spring patrolling of Pepperwood Creek in hip-boots, stooping to reach under boulders and undercut banks and then recording the identification of squirming newts by examining all their toes, as exhausting. But the "mountainous expanse of virgin forest and springtime meadows drained by rivularis-ridden streams" rewarded the field scientists with lots of data and much to discuss every night at the station's outdoor barbecue pit.

One of the extras of working as a field biologist is finding beautiful newt pools like this one.   
Consistent results of the recaptures led them "to think of the population of the experimental stretch of being a mosaic of separate subpopulations", a precision they had not imagined before the field study. From 1953 to 1964, the Twitty team marked and relocated over 20,000 newt residents of Pepperwood Creek and although once a marked red-bellied newt was found in another creek on the ranch, all the remaining recaptured newts were found in the experimental stretch of Pepperwood Creek and almost always very close to where they were originally collected.

Pepperwood Creek newts were also relocated to two other streams, one and three air miles away and across steep mountainous terrain equal to many more miles for the traveling newt. Within five years, 81% of the original 692 newts displaced to the creek one mile away had returned to Pepperwood Creek. By placing land traps en route from these other creeks, the researchers were able to determine that the newts made their return trip by a somewhat direct overland route, not by navigating connecting streams. Furthermore, some of the newts waited in the creek at their displaced location for two or three years yet still returned to Pepperwood Creek in a subsequent year.

The rough terrain of Danfield, Pepperwood, and Jim Creeks in Sonoma County, California. This is a 1993 image, however, it looks similar to the undated aerial photograph used by Twitty in Of Scientists and Salamanders published in 1966.   
In another experiment, red-bellied newts were moved from Danfield Creek to Jim Creek five air miles away. By the second year, 134 of the original 730 relocated newts had made it back to Danfield Creek. Many of the original Danfield newts were captured in land traps on ridges between the two creeks, again showing that they returned over land. Interestingly, Pepperwood Creek is situated in a canyon between these two other creeks, and at least in the first two years of this experiment, a few dozen of the Danfield newts temporarily stopped in Pepperwood Creek but then subsequently continued on to Danfield Creek.

After many years of research into the red-bellied newt's fidelity to its breeding stream, much of it funded by the National Science Foundation, Twitty concluded:
Homing seems to be an all-or-none phenomenon: the animals either accept the release sites - as they seldom do - or, once initiating the return journey, refuse to stop short of its completion . . . the route taken by the homing animals is almost entirely on land, along the mountainside, not in the stream channel itself. The extreme roughness of the terrain, cut at frequent intervals by deep gullies makes the homing journey all the more difficult and accordingly all the more impressive.
If the weather was rainy or overcast in the winter or early spring, we sometimes found red-bellied newts climbing up steep slopes in the Stevens Creek watershed. It was difficult to follow them up such rough terrain and to be patient with their newt speed.   
When we found red-bellied newts in the Stevens Creek watershed, we tried to detect a pattern of where they were moving. Winter rains should have signaled their appearance from underground, terrestrial feeding and then migration to their breeding waters, yet we were often confused to find red-bellied newts doggedly heading up a steep incline or tumbling down a trail bank, and not in a direction that would have been the easiest route to Stevens Creek. After reading Twitty's homing experiments, we realized how capable these newts were of crossing long distances and rugged terrain, and that perhaps the main stem of Stevens Creek was not their ultimate destination. We rechecked the topographical maps for all the blue lines indicating tributaries and tried again to line up the dots of our observations with some type of newt route. We noticed that we were finding many more newts migrating on land and very few newts in the water. Were we missing the actual breeding season or was there another tributary for us to discover? Just where was our Pepperwood Creek?

Newts frequently surprised us during our Stevens Creek surveys by tumbling down trail banks and diving off barriers only to land on their backs. With waving of red palms and some tail whipping, they quickly flipped themselves over unhurt and continued on their way.   
Twitty and students went on to test other aspects of the newt's homing ability including what senses may aid them in orientation. The Twitty team surgically removed eyes and snipped the olfactory nerves of newts and repeated some of the relocation experiments or invented new experiments with various contraptions. These experiments were in their early stages by 1965 and the Twitty team had tentatively concluded that the loss of eyesight negatively affected the ability of many newts to feed, however, it did not appear to be a primary deterrent to the skinny newts' ability to return to their breeding stream. Olfactory-deprived newts were less likely to return to their home stream. However, the initial experimental results were confounded by the ability of newts to regenerate their olfactory nerves within 3 years (as determined by dissection of the returned newts), and new olfactory studies were under consideration.

We would occasionally find California newts with abnormal growths in the Stevens Creek watershed. This California newt had two additional small feet growing behind its left hind leg. 5/9/2010.   
Sometimes I would choke when I got to the parts in Dr. Twitty's publications about snipping off toes of the newts, removing legs, opening up their skulls to clip the olfactory nerves, and relocating newts farther and farther away as part of their experiments to test the red-bellied newts' incredible ability to return to their breeding streams. Frankenstein of the salamander world, I heard someone describe him. I was conflicted by my need to know more about the behavior of red-bellied newts to interpret the circumstances of the lost population at Stevens Creek and my aversion to some of the experimental practices commonly used back then. Yet at that time, these types of animal behavior experiments were not unusual and less invasive techniques were not available.

This California newt had an extra right hind leg. The upper leg would rotate in circles similar to the pattern taken by the operational lower leg. 2/10/2014   
Twitty was not without remorse when handling these handicapped newts. When describing one of the sight experiments in which red-bellied newts were blinded and then marked by removing one hind limb and displaced one-quarter of a mile downstream, he shared:
Of the countless displaced newts that I have handled, I think none has made such an impact on me as the first one of these blinded animals to be recaptured. As I examined its empty eye-sockets and emaciated body, and then looked downstream toward the heavy forest and rugged terrain it had traversed in coming home, my respect for its accomplishment came as near to awe and reverence as can be inspired by lowly organisms or possibly even by their highly evolved descendants. 
Decades of research including over 50 scientific publications have tightly tied Twitty's name to that of salamanders and particularly the red-bellied newt. In all this time, in all these studies, did Twitty or any of his students bring red-bellied newts back from their field research center at Pepperwood Creek in northern California to Stanford and then release them in the nearby Stevens Creek watershed? Nowhere in any of his publications did Twitty ever recognize the Stevens Creek population of red-bellied newt although he and his associates certainly explored the streams and hills surrounding Stanford.

Nowhere could we find evidence that they knew, much less introduced, the Stevens Creek population. And we can't ask Twitty about his knowledge or involvement with this population of red-bellied newts because 42 years before our discovery in the canyons of Stevens Creek, yet just six months after publishing his book Of Scientists and Salamanders, Twitty committed suicide.

On March 22, 1967, Dr. Victor Chandler Twitty wrote a note to his wife of 33 years and then took a lethal dose of cyanide in his Stanford laboratory. Cyanide was commonly used in laboratories to dispatch experimental animals for post-mortem examination. If one is knowledgeable about chemicals, as surely Twitty was, cyanide can be administered to provide a quick, peaceful death. Indeed, in the late 1950's, there was a popular novel and movie On The Beach in which the entire population of Australia and a few remaining American submariners ingest cyanide pills after a nuclear holocaust and fall to sleep, the final sleep of all humans on this earth.

The cover of the 1968 paperback edition of On The Beach.
The title page has a quote from a T.S. Eliot perhaps to further reflect on the atomic anxiety of world citizens at that time:
This is the way the world ends
This is the way the world ends
This is the way the world ends
Not with a bang but with a whimper.

A 1959 film starred Gregory Peck, Ava Gardner, Fred Astaire and Anthony Perkins.      
We do not know why Dr. Twitty committed suicide. A brief news item in the New York Times noted that Dr. Twitty "was to have retired in June and had been concerned about his health for some time." In the eulogies, writings of other Stanford professors, and a biography prepared by the American Academy of Sciences, Twitty is described as a respected scientist and committed teacher. Friends fondly recall the summer high-teas at the Twitty home on Alvardo Row on the Stanford campus where students and professors, science and humor were equally welcomed.

Every time I read his popular book, Of Scientists and Salamanders, I hear a content voice, happy with his accomplishments and excited about planning the next field season at Pepperwood Creek. Dr. Twitty is certainly recounting his academic career, but his intentions seem two-fold in the book: to share the amazing adaptations of the red-bellied newt and to show others that a worthy career can be shaped in an unconventional way despite pressure to do otherwise.

His early career years were at the time of the Great Depression and World War II, yet in the academic halls and basement labs of Stanford and prowling the wild hills of California, he seemed far away from those world events which burdened others of his generation. By the spring of 1966, the first sit-in had occurred at the Stanford campus protesting the United States' involvement in the Vietnam war, and some students had started to investigate and object to classified research at the university which was funded by the federal government and allied industry to support jungle reconnaissance and chemical and biological warfare (Wells 2011).  Although they did not occur until after Twitty had died, violent protests in 1968 and 1969, including arson, bombings, police intervention and the suspension or dismissal of some students and professors, were preceded by growing tensions on the Stanford campus.

There were other changes occurring at Stanford in the 1960s that would have affected Twitty as head of the Biological Sciences Department. University administrators were focused on developing "steeples of excellence" and directed departments to concentrate on research of national importance that could be funded by large government grants. Twitty and other staff of the biology department objected to Provost Frederick Terman's attempts to move the department away from the study of organisms and to direct more funding and research towards molecular biology and biochemistry (Timby, 1998). Some professors left and Twitty, after serving in that role for 15 years, resigned as executive head of the biological sciences in 1963 and went on a one-year sabbatical.

Perhaps Twitty was referring to these pressures when he closes Of Scientists and Salamanders with:
Discriminatory judgements about the importance of different fields or levels of biology are in my opinion intellectually naive . . . To any young - or even aging - laboratory biologist who has a little spare time and feels that molecules and cells are moving in on him too menacingly, I suggest he scan his circle of acquaintances for a landowner who might loan him a rural niche where the flora or fauna can be tinkered with . . . he can refresh himself afield and still maintain his foothold in the laboratory.
My well-thumbed copy of Of Scientists and Salamanders which I bought used since it is out of print. I was a little chagrined to realize this was a discard from the Marin County Library.   
There have been moments when I have wondered if a chaos existed after Twitty's sudden death which caused the numerous newt experiments to be abandoned and perhaps study newts at Stanford were released in the Stevens Creek watershed. When we spoke to those few remaining associates of Twitty's that we could find, mostly retired, they adamantly stated that they had never released newts in the Santa Cruz Mountains. By that time, the Pepperwood Creek field station was so well established, there is nothing to indicate that any adult red-bellied newts were at the Stanford campus in 1967.

I cannot find Twitty's papers. The archivists at the Stanford library say they were probably given to the California Academy of Sciences, and the librarian and salamander experts at the Academy say they do not have them. And so I have come to the conclusion, in the absence of any other evidence, that Twitty had nothing to do with the appearance of red-bellied newts in Stevens Creek, and that his and my adventures with the dark-eyed stranger are independent.

Although I have sometimes wanted a reason and slipped into the dark side of speculation, why Twitty committed suicide does not matter. Just as he decided to pursue his research in the field instead of solely with a microscope, so he decided on the way to end his own life. He deserves respect for his remarkable career and finding his own way to learn, to teach and to share the wonder of salamanders.

There is, however, another possible Stanford-Stevens Creek connection. The Twitty associates we talked to were those who were conducting research at Stanford in the 1950s and 1960s. Twitty began collecting red-bellied newt eggs in Ukiah in 1935. In that period of approximately 20 years, Twitty and an earlier set of his students were experimenting with red-bellied newt eggs and hybrid larvae as evidenced by their many publications, and in this pre-Pepperwood Creek period we can assume these experiments and thus newt eggs and larvae were housed at the Stanford campus. What happened to those early research subjects? At the end of the experiments, were they preserved in formaldehyde or flushed down the sink, or were they released into a nearby mountain stream? Is it possible this population had initially been introduced in the 1935-1953 period and remained cryptic for sixty years? Likewise, hidden in the final pages Of Scientists and Salamanders, there is a passing reference to red-bellied newts at the Stanford lab in the late 1960s, "Large samples of the resulting second-generation embryos have been brought back to Stanford at the end of the spring seasons for observation and rearing in the laboratory." What happened to those hybrid Taricha newts?

The Stevens Creek watershed - calling newts and calling newt followers.   
Perhaps the genetic study underway by the Berkeley team would show a molecular connection between the Stevens Creek newts and those previously collected by Twitty in Sonoma County, or even show evidence of hybridization. Also, in the back of my mind, I had a vague recollection that Stanford University once owned some land in the Stevens Creek watershed. Could I find a connection? But most immediately, we needed to find eggs to confirm this was a breeding population and get an idea of how long this population had homed in on Stevens Creek.

To be continued as A Newt Egg Crawl.
This post is the ninth in a series on the discovery of red-bellied newts in the Santa Cruz Mountains of California. To start at the beginning of the series go to Mystery of the Red-Bellied Newt.

Rough-skinned newt, Taricha granulosa
California newt, Taricha torosa
Red-bellied newt, Taricha rivularis

See also:

Eliot, T. S., 1939, "The Hollow Men", Collected Poems 1909-1935, Harcourt, Brace and Company, Inc.

New York Times, March 23, 1967, Stanford Biologist Dies in Laboratory of Self-Poisoning.

Shute, Nevil, 1957, On The Beach, Heinemann, London.

The Stanford Daily, April 3, 1967, Twitty Takes Own Life.

Timby, Sara, Fall 1998, The Dudley Herbarium - Including a Case Study of Terman's Restructuring of the Biology Department, Sandstone and Tile, Stanford Historical Society.

Twitty, Victor Chandler, 1966, Stanford University, Of Scientists and Salamanders, W.H. Freeman and Co., San Francisco. All quotes in this post are from this book.

Wels, Susan, editor, Winter 2011, The Troubles at Stanford: Student Uprising in the 1960's and '70s, Sandstone and Tile, Stanford Historical Society.

Wessells, Norman K, 1998, Victor Chandler Twitty, 1901-1967, A Biographical Memoir, National Academy of Sciences.

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