According to About.com, experts believe maracas were invented by the Tainos who were the native Indians of Puerto Rico during the 16th and 17th centuries. The original maracas were made from fruit and had a round shape.
Maracas are considered one of the easiest instruments to play because they make sounds by shaking. About.com notes that the first maracas made sound by replacing the pulp found in the fruit with tiny pebbles. A pair of maracas will sound different because each one will have a different amount of pebbles within them. Modern maracas are now made from plastic and are very popular in Latin America.