An experiment is underway (On the threshold of consciousness) (1968)

Chronicle: I.P. Pavlov observes experimental animals.

Chimpanzees take something out of a box.

Pavlov's experiments with monkeys.

A chimpanzee draws.

Two monkeys communicate with each other.

Scientists in a laboratory listen to the sounds of great apes' voices recorded on tape.

A monkey in a cage.

A man approaches the cage with a monkey and shakes its hand.

The monkey tries to get a tree branch with a stick.

Baby chimpanzees in a cage.

A baby chimpanzee drinks milk from a bottle with a nipple.

A small monkey plays in a playpen.

A chimpanzee eats grapes.

A chimpanzee screams.

A chimpanzee is in the arms of an employee.

An employee brought food to the monkeys, they greet him with joyful screams.

A chimpanzee eats porridge with a spoon.

Chimpanzees eat pineapple.

A chimpanzee reacts to a light signal.

A chimpanzee plays with water.

Scientists observe how monkeys react to different situations.

A troop of baboons in an enclosure.

A baby with its mother.

Females communicating with each other.