Pecans are a type of large deciduous tree. Its native continent is North America, where they are said to have been a staple diet for the local Indian population. They were referred to as pecans, which are nuts that are too tough to be manually crushed. The nuts themselves, however, have a very delicate flavor and scent. They are sweeter than walnuts, despite their resemblance. Only in the sixteenth century did they arrive in Europe, from which point they were gradually dispersed throughout Africa, Asia, and Australia. Because to their high nutritional value and reputation as one of the tastiest nuts, pecans were a staple of the diet of the first American astronauts.