In July 2007, a fascinating story emerged in the New England Journal of Medicine about a cat that could "predict" the deaths of patients in a nursing home several hours before they died. Oscar, a cat adopted by the staff of the Steere House Nursing and Rehabilitation Center in Providence, R.I., has at least 25 successful predictions, in which patients died hours after the cat sat down by their beds. After the nursing home's staff caught on to Oscar's ability, they began alerting families whenever the cat took up his post next to a patient. Most families tolerate or even welcome his presence, though Oscar becomes upset if forced out of the room of a dying patient, meowing outside the door.
Oscar's actions appear deliberate. He regularly wanders around the home's unit for patients with advanced dementia. He sniffs and watches a patient before sitting down with her. Oscar then purrs while sitting with the patient and usually leaves soon after she dies.
How does Oscar do it? Is it a "sixth sense," a unique scent he smells or something else? Animal experts have put forth a variety of explanations, though most agree that it likely has to do with a specific smell produced by dying patients. That is, people who are dying emit certain chemicals that aren't detectable by other humans but that may pique Oscar's heightened sense of smell. An expert on felines said that cats can sense sickness in their human and animal friends [Source: BBC News]. Jacqueline Pritchard, a British animal expert, told BBC News that she was certain that Oscar was sensing vital organs shutting down [Source: BBC News].
As for why he keeps vigil next to patients, Oscar may be mimicking the behavior of staff who spend time with dying patients. One animal expert suggested that it may be as simple as Oscar enjoying the comfort of heated blankets placed on dying patients [Source: NPR].
Stories of animals with startling abilities aren't rare. Tales have long existed of dogs detecting various types of cancer with their sense of smell. A study later proved that dogs could sense evidence of bladder cancer by smelling it in urine. Some people who suffer from serious epilepsy use specially trained dogs provided by charities. These dogs warn their owners of impending seizures by licking or some other signal. One woman said that her dog regularly gives her a 40-minute warning, allowing her to get to a safe place so as not to worry about the seizures putting her in danger [Source: BBC News].
The seizure-sensing dogs look for subtle smells and changes in features of their owners (such as dilated pupils). Their training, which takes at least a year, teaches them to warn their owners. While we're used to hearing about dogs learning to help the blind or search out injured people, Oscar's case is more puzzling. Cats, unlike dogs or even elephants, aren't associated with altruistic, empathic behavior. Scientists believe that dogs can sense disease in others because of their evolutionary origin as wolves, who needed to be able to detect when someone in the pack was hurt or sick.
We've found some rational explanations for Oscar's actions and those of seizure-sensing dogs -- subtle smells, dilated pupils, learned behaviors -- but what about other strange animal behavior? Can some animals really sense earthquakes or feel compassion? On the next page, we'll delve into the world of ethology.
Ethology and Strange Animal Behavior
Ethology is the study of animal behavior, based in zoology. Ethologists study the evolutionary basis and development of animals' innate behaviors, like a spider knowing how to make a web without learning from a parent. They also study forms of communication (physical, chemical, visual) and social interactions between animals. Human ethology research looks at the evolutionary origins of human behavior and also compares behaviors across cultures. Other studies of animal behavior are based in psychology, focusing on things like learned behavior and teaching behaviors to animals and applying the results to humans.
One common question about animals that can be considered through the lens of ethology is whether animals have special sensing abilities. For thousands of years, stories have spread about animals sensing earthquakes. Just before the 2004 tsunami that ravaged parts of southern Asia, many animals exhibited strange behavior or ran (or flew) to higher ground. By some accounts, rescue workers found a surprisingly low number of dead animals, though there were areas where many dead animals, particularly cattle, were discovered.
Is this another case of a special "sixth sense" or supernatural ability? Some scientists propose that sophisticated hearing and the ability to detect subtle vibrations allow animals to sense earthquakes. Some also suggest that animals detect changes in the air or in electromagnetic fields. In any case, it's likely not a mysterious sense but rather one or two senses -- such as hearing and smell -- that are so highly refined that animals can hear an earthquake or smell gases released by that earthquake. Alan Rabinowitz, of the Wildlife Conservation Society, claims that humans once had this ability but lost it through evolution [Source: National Geographic]. (CBS' "60 Minutes" produced a remarkable story explaining how the seafaring Moken people used their close connection to the ocean to detect the tsunami before it happened.)
It's very difficult for scientists to pin down exactly what causes animals to flee or panic before an earthquake. Numerous such stories exist, but a reliable testing method does not. After all, animals respond to many stimuli, some of which are difficult to trace. Critics also say that people remember their pets' acting differently only because an earthquake happened, and that pets often exhibit strange behaviors with no subsequent earthquake or disaster. But the theory of animals' sensing earthquakes has gained enough ground that scientists around the world have attempted to test it, with mixed results.
Not only do some animals have highly refined senses, but many experience sophisticated emotions as well. Frans B.M. de Waal, a noted primatologist at Emory University, says that a variety of animals -- not just cats or dogs, but even rats -- feel empathy and other emotions [Source: Scientific American]. In one study, scientists injected mice with a chemical that gave them slight stomach aches. The natural behavioral response is stretching, and injected mice stretched more when placed next to injected mice than they did when placed next to non-injected mice. Male mice also showed less of a response around males that they didn't know. In other words, not only do mice show a response to the pain of others, but it matters who the other mouse is. University of Chicago neurobiologist Peggy Mason called this "a significant step toward human-like social feeling" [Source: Scientific American].
For more information about animals predicting death, ethology and related topics, please check out the links on the next page.
Related HowStuffWorks Articles
More Great Links
- "Can pets sense illness?" BBC News. July 27, 2007. http://news.bbc.co.uk/2/hi/uk_news/magazine/6919063.stm
- "Cats' "Sixth Sense" Predicting Death?" WebMD. CBS News. July 25, 2007. http://www.cbsnews.com/stories/2007/07/25/health/webmd/main3097899.shtml
- "Does Feline Have a Feeling That Death Is Near?" Associated Press. NPR. July 26, 2007. http://www.npr.org/templates/story/story.php?storyId=12249387
- "Introduction to Ethology." http://cas.bellarmine.edu/tietjen/Ethology/introduction_to_ethology.htm
- "Sea Gypsies Saw Signs in the Waves." 60 Minutes. CBS News. June 10, 2007. http://www.cbsnews.com/stories/2005/03/18/60minutes/main681558.shtml
- "US cat 'predicts patient deaths.'" BBC News. July 26, 2007. http://news.bbc.co.uk/2/hi/americas/6917113.stm
- Dobbs, David, de Waal, Frans B.M. and Mason, Peggy. "Do animals feel empathy?" Scientific American. July 24, 2007. http://blog.sciam.com/index.php?title=animal_empathy&more=1&c=1&tb=1&pb=1
- Mott, Maryann. "Can Animals Sense Earthquakes?" National Geographic News. Nov. 11, 2003. http://news.nationalgeographic.com/news/2003/11/1111_031111_earthquakeanimals.html
- Mott, Maryann. "Did Animals Sense Tsunami Was Coming?" National Geographic News. Jan. 4, 2005. http://news.nationalgeographic.com/news/2005/01/0104_050104_tsunami_animals.html
- Radford, Benjamin. "Voice of Reason: The Myth of the Tsunami Survivors' Sixth Sense." Live Science. April 21, 2005. http://www.livescience.com/animals/050421_tsunami_myths.html