>- several baby monkeys were born and raised in a controlled lab environment
>- although their mothers were born wild and may have seen snakes, the lab-born baby monkeys were never exposed to snakes
>- the baby monkeys were temporarily separated from their mothers (so they couldn't get behaviour cues from their mothers)
>- while each baby monkey was in its cage, a large (but harmless) snake was released into the same room
>
>In every case, the baby monkeys showed extreme fear of the snake. Even though they had never seen a snake before in their lives and had no way to know that they "should" be afraid of snakes.

We had an accidental experiment of the sort. A dog was brought in as a puppy, a day or two old, and has never left the yard. At age of three, it caught a rat like a real pro, knowing exactly how to jump on it and how to break its neck with the first bite. How did it know what to do?