When two white-faced capuchin monkeys meet, they say hello by sticking their fingers into each other's noses.
In 1945, Dwight D. Eisenhower predicted that people would try to dispel the holocaust as a falsehood, and ordered all possible photographs taken of the Nazi crimes to hinder any such attempts.
Donkeys and dolphins are sometimes used as guard animals.
The first TV commercial didn't air until the 1940s.