If it weren’t for Sultan and his primate clan, the study of animal behavior would have taken a very different path. Sultan, a male chimpanzee (Pan troglodytes), and five wild females were captured as juveniles in South Cameroon and made captive in 1912. They were housed on Tenerife, a Canary Island off North Africa, until 1920, during which several chimpanzees were added. Research on these chimps, led by German psychologist Wolfgang Köhler, laid the groundwork for comparing how animals behave, or the field of “comparative psychology.”
A recent paper published in the journal European Psychologist tracked the fate of Köhler’s chimpanzee study subjects after they were moved from Tenerife to a zoo in Berlin. Led by University of Auckland psychologist Javier Virués-Ortega, the paper represents the culmination of archival-style detective work—analyzing newspapers, photos, zoo records, letters, memoirs, museum specimens, public records, and interviews—to piece together the final years of the famous Tenerife chimps.
“These chimpanzees are usually remembered for what they revealed about the mind,” said Virués-Ortega in a press release. “We wanted to ask the historical question textbooks mostly leave out: What happened to the animals themselves?”
In Tenerife, Köhler’s observations revealed that chimps, like humans, made tools. In a particularly memorable moment, Sultan stuck together two bamboo sticks to reach for a banana outside his cage. During experiments, the chimps also proved capable of “insight,” a quality previously ascribed only to humans, in designing complex solutions to problems.
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Although the research showing cognitive parallels between chimps and humans was groundbreaking, funding problems and friction with authorities caused the shutdown of the Tenerife research station. The old “Casa Amarilla” sat abandoned, explained Virués-Ortega, conveying a “historically charged feeling even before you know the full story” of what happened to the chimpanzees.
The group of surviving chimps, including Sultan, traveled by steamship in 1920 to the Berlin Zoological Gardens and were received with much fanfare. But, despite the fame they had acquired, the archival evidence showed that the chimps’ lives went downhill from there.
Captive conditions on Tenerife had included outdoor play space, a diverse fresh diet, and a mild climate. In contrast, Berlin Zoo proved too cold in the winter, especially with limited heating fuel in the aftermath of World War I. Food supplies were affected by the war as well, which imposed a low-nutrition diet of bread and potatoes. Although the chimps received what Virués-Ortega describes as “advanced medical attention for the period, to the point that several leading German medical figures became involved,” they still failed to thrive.
Sultan died in late February 1923 at about the age of 16, outliving the females, three of whom perished in the bitterly cold winter of 1921-1922. None of the Tenerife chimps attained their natural lifespans of upward of 30 years.
Most of the chimps died of a parasitic infection called balantidiasis, undoubtedly compounded by the unsuitable temperatures, malnutrition, and confined quarters. But, as the study authors point out, their lives were also likely shortened by the stress of moving to a setting where they experienced heightened contact with humans, disrupting their social network. One newspaper account described a female chimp begging a cigarette off a zoo visitor, and then puffing on it “like a woman of today.”
“From today’s perspective, aspects of their treatment would clearly be considered unethical, including social isolation, lack of environmental enrichment, insufficiently heated housing, and circus-like displays,” said Virués-Ortega. “However, formal animal-welfare guidelines and modern ethical standards for great-ape care were still decades away.”
Their suffering wasn’t for naught, though. Their tenure at the Berlin Zoo brought to light the impacts of captivity, such as “numerous problem behaviors that you do not see in the wild, like stereotypy (repetitive movements), coprophagia (eating feces), and apathy,” explained Virués-Ortega, and contributed to improving zoo care. And their work with Köhler, of course, established great apes as “crucial subjects of interest in studying intelligence and its evolution” as well as how animals can show insightful, problem-solving behavior that can teach humans a little something about ourselves, too.
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Lead image: A photo of the chimpanzee named Sultan, taken in Tenerife circa 1914. Credit: Zentrum für Geschichte der Psychologie, Julius-Maximilians-Universität Würzburg
