Chimpanzees famously solved puzzle that transformed human understanding of intelligence, but their move to Berlin ended tragically
More than a century ago, a small group of chimpanzees revolutionized the way scientists understand intelligence. Through a series of groundbreaking experiments on the Spanish island of Tenerife, the apes demonstrated that they can use insight to solve problems rather than relying solely on trial and error—a discovery that challenges long-held assumptions about the uniqueness of human reasoning.Yet while their scientific achievements are well known, the fate of the chimpanzees themselves has been largely ignored. According to a study published in the journal “The Fate of the Sudanese Clans” by Dr. Javier Verrues-Ortega european psychologistnewly examined archival records reveal what happened to the famous chimpanzees after they were moved to Berlin.
Chimpanzees who changed psychology
The Prussian Academy of Sciences established the Great Ape Research Station in Tenerife in 1913, with German psychologist Wolfgang Kohler serving as its director from 1914 to 1920. During this time, he conducted groundbreaking experiments that reshaped scientific understanding of animal intelligence.To answer this question, Kohler designed a series of experiments involving a group of chimpanzees, including Sultan, Rana, Chica, Grande, Tercera and Tschego. Instead of teaching them through repeated rewards, he presented them with unfamiliar problems that required planning and creativity. In one of the most famous experiments, bananas were hung out of reach, while wooden boxes were scattered around a fence. Instead of endless failed attempts, some chimpanzees stacked the boxes to form a platform and climbed up to retrieve the fruit. Another landmark experiment involved placing sticks near food out of the animals’ reach. The Sultan realized that two short sticks could be joined together to create a longer tool capable of pulling food closer. These solutions seem to emerge through sudden understandings or “insights” rather than gradual trial and error. These experiments became landmarks in comparative psychology and helped establish that chimpanzees possess complex cognitive abilities, fundamentally changing scientific thinking about animal intelligence.
Chimpanzee skull named Rana-Loca (Image: Javier Virués-Ortega, University of Auckland)
From science stars to forgotten lives
Although Kohler’s experiments are world-famous, the chimpanzees’ subsequent lives have received little attention.After the Tenerife research station closed in the 1920s, the six surviving chimpanzees were transferred to Berlin Zoo. For decades, historians knew little about what happened after their arrival.The new study used zoo records, letters and other historical evidence to piece together their fate. The findings show that life in Berlin is far removed from the carefully managed research environment of Tenerife. Born in the tropical forests of Cameroon, these chimpanzees struggled to adapt to Berlin’s harsh winters. After World War I, the zoo also faced severe financial difficulties, which resulted in insufficient heating and a diet low in starch, with bread and potatoes replacing fresh fruit. Combined with illness, pregnancy, and social unrest within the group, these conditions are thought to have contributed to the premature deaths of several chimpanzees.Researchers also rediscovered the well-preserved remains of several members of the Sudanese clan at Berlin’s Museum of Natural History, which had remained unidentified for decades. Modern DNA analysis of these remains may help researchers better understand chimpanzees’ origins and genetic relationships while preserving an important part of psychology’s history.The study also documents how the chimpanzees endured economic hardship during the interwar years, which further affected conditions at Berlin Zoo. Their welfare continued to decline, and one after another the chimpanzees that had helped reshape psychology disappeared from the historical record. Only later did researchers begin to reconstruct their forgotten stories through archival evidence.
Why their legacy still matters
Researchers believe it is as important to remember the lives of chimpanzees as it is to celebrate their scientific breakthroughs.Today, research continues to show that chimpanzees use tools, cooperate with each other, plan ahead, and display complex social behaviors. Many of these discoveries built on the foundations laid by Kohler’s pioneering work in Tenerife.However, new historical inquiry reminds us that scientific progress often depends on living animals, whose welfare deserves equal attention. By tracing the lives of the Sudanese clan outside the laboratory, the researchers highlight the need to acknowledge not only their role in advancing knowledge, but also the hardships they endured after their experiments ended.More than 100 years later, the stories of Sultan, Rana, Chica, Grande, Terceira, and Chego have become both landmarks in the history of psychology and a powerful reminder of the ethical responsibilities that accompany scientific research. Their extraordinary intelligence transformed the way humans think about other animals’ minds, while their final years were widely ignored, highlighting why compassion and animal welfare must remain at the heart of modern science.
