How come humans dont know where babies come from as kids... but animals find out without anyone telling them?

I've bred German shepherd dogs for over 40 years. Dogs have the general idea, but learn the needed details by watching mating adult dogs.

Humans have the longest period of growing up and maturing than any other animal. We seem to focus on experiencing and absorbing knowledge, whereas most other animals have to grow up quick and fight for survival. Animals won't know that copulation will lead to children, they just are driven to do it. In fact so are we, once we start to develop our sexual urges - even though we know the risk of pregnancy, still the urge is overwhelming. Most animals hit their sexual capability and the ability to conceive after a year. For us it takes anything between 10 and 15 years.