FIFA said the mascot, unveiled by former Brazil striker Ronaldo during a television programme late on Sunday, represented the three-banded armadillo, an endangered species indigenous to Brazil.
While nature's version is light brown in colour, FIFA's mascot is yellow with green eyes and a blue shell, the colours of the Brazilian flag, and will be holding aloft a football.
Other mascots over the years include 'Zakumi' the leopard from South Africa 2010, 'Pique' the chillipepper from Mexico 1986, and a lion named 'World Cup Willie' from England in 1966.
"The mascot will play a key ambassadorial role in the next two years," said Ronaldo, who played in three World Cups and was an unused squad member in 1994, on Brazilian television.
"I'm sure he will inspire many young football fans in Brazil and all over the world with the great passion which he has for the sport and for his country."
Three-banded armadillos live mainly in Brazil's arid northeast and are threatened by habitat destruction. They are unusual among armadillos in that they can roll up into a ball to defend themselves from predators.
"The fact that the three-banded armadillo is a vulnerable species is very fitting," said FIFA Secretary General Jerome Valcke.
"One of the key objectives through the 2014 World Cup is to use the event as a platform to communicate the importance of the environment and ecology.
"We are glad to be able to do so with the help of a mascot who I'm sure will be much-loved, not only in Brazil, but all over the world."
FIFA said a vote would be held to choose the mascot's name. A shortlist of three names has been picked by a committee including former World Cup winner Bebeto, include Amijubi, Fuleco and Zuzeco. The result of the public vote will be revealed in November.
"The mascot is one of the key visuals of a FIFA World Cup, providing FIFA, the LOC (local organising committee) and other stakeholders with a strong and exciting brand asset through which promotional campaigns can be activated and target audiences can be engaged," added FIFA in a statement.
- FIFA World Cup