Adriaan Kortlandt

Kortlandt demonstrates how a goat responds to his goatlike attack. Adriaan Kortlandt (25 January 1918, Rotterdam – 18 October 2009, Amsterdam) was a Dutch ethologist. He has been described together with Vernon Reynolds and Jane Goodall as "...one of a trio of pioneers ... who founded field studies of chimpanzees in the 1960s."

Early life and education

Adriaan Kortlandt was born on 25 January 1918 in Rotterdam, Netherlands. From a young age he was fascinated by animal behaviors, spending time observing cormorants near his home.

Kortlandt studied biology at the University of Utrecht, His work provided insights into the rigid nature of instinctive behaviors in cormorants and their importance for species survival. and Tinbergen independently identified the behavioural phenomenon that is now called displacement activity (Dutch: overspronggedrag)and the hierarchy of instincts. if in a cormorant or an avocet a fighting impulse is thwarted for one reason or another, the bird will perform sexual and nesting behaviour. Further, if a sexual impulse is thwarted, the bird will peck its mate or make nesting movements. A nesting impulse when thwarted may give rise to sexual or fighting activities. ("Vice-versa principle".) Apparently there exists some nervous mechanism or centre uniting or connecting these three activities and this mechanism or centre. The most striking phenomenon was their obvious fear of hurting the pads of their paws on the spines. They could easily have swept away the thorn branches, or lifted them up, with just one gentle movement of a paw, but they were much too afraid to do so. better known under the name given by French paleoanthropologist Yves Coppens: "East Side Story".