Behavior can be modified by learning but some apparent learning is mostly due to maturation. Imprinting is a learned behavior with an innate component acquired during a critical period. Exogenous cues have little influence on biological clocks. The proposed mechanism of the biological clock involves the resonance of magnetite. Circannual behaviors are controlled by endogenous clocks.
Hibernation is controlled by an internal clock.
Karl von Frisch 2. Niko Tinbergen 3. Konrad Lorenz 4. B.F. Skinner 5. Ivan Pavlov 13.