Zoopharmacognosy is the ability of some animals to know, seek out and use certain plants for their medicinal value to cure what ails them.

This definition is my own because so far I haven't been able to find an "official" dictionary definition. The earliest use of the word I've found was in 19921.

Zoopharmacognosy is a relatively new field of study, so there is as yet no exhaustive body of research on the topic. However, this has not stopped Barnes & Noble from publishing a book about it.2

My own interest was drawn to to the subject by an article in Die Welt4 which cites the following anecdotal evidence by researchers observing primates:

  • An orangutan, obviously suffering from a headache, held his head and went over to a certain plant and ate some of its flowers. He seemed to be better within an hour. At another time, when the researcher himself was suffering from a headache, he bravely followed the ape's example and found his headache abating soon afterward.
  • Another pair of researchers, one of them Michael Huffman, currently the biggest name in zoopharmacognosy, observed a female chimpanzee who withdrew from the group because she was suffering from diarrhea. She sought out a mjonso tree, normally shunned by the chimpanzees because of its bitter and poisonous leaves and bark. This time, however, she peeled some of the bark from a twig, chewed on the pith and swallowed the juice. The next day the chimp was back to normal.

    An analysis of the substances in the mjonso tree juices revealed 13 hitherto unknown substances with antibacterial, antiparasitic and even antitumor effects.3 It turns out the plant is valued by the African locals for its over 25 medicinal properties.

  • Sometimes animals eat plant components for their physical properties rather than their chemistry. Chimpanzees are frequently observed to eat the bristly leaves of certain plants, swallowing them unchewed. These leaves have no nutritional value and pass the digestive system crinkled but intact. But closer examination of the leaves shows that they often trap parasitic worms from the animals' intestines on their bristles. Some evidence for the conscious use of these leaves is found in the fact that only sick chimpanzees eat the leaves, and mostly after the beginning of the rainy season, when the number of parasitic larvae and the danger of infection are at a maximum.

Other sources5 quote similar discoveries about primates and other animals, including bears, turtles and even a porcupine. Study of primates shows that knowledge about beneficial plants is passed on from parents to young during the long course of their upbringing. How other species acquire this knowledge is still a subject undergoing investigation.


References
  1. Rodriguez, E. and R.W. Wrangham. 1992. Zoopharmacognosy: Medicinal plant use by wild apes and monkeys. Paper presented at the 1992 American Association for the Advancement of Science (AAAS) meetings. Chicago, Illinois.
  2. Engel, Cindy. Wild Health. Barnes & Noble, January 2002.
  3. http://veederandld.20m.com/greports/2501b.html
  4. http://www.welt.de/daten/2002/04/20/0420med327251.htx
  5. http://jinrui.zool.kyoto-u.ac.jp/CHIMPP/CHIMPP.html