The name of the archipelago comes from the bird that corresponds to the second largest population of birds in the place, with around 3 thousand individuals: the brown booby, which is also known as "al catraz", a term that in Arabic (الغطاس) means "the diver" - due to their ability to dive into the sea and capture fish or squid.

     Alcatrazes is the largest breeding site for seabirds on the Brazilian coast, with a population of around 10 thousand birds. Furthermore, due to its diversity of flora and fauna, with more than 20 endemic species, the archipelago is known as the "Galápagos of Brazil", and attracts an increasing number of researchers. It has unique importance for Brazilian marine biodiversity, having more varieties of fish than Fernando de Noronha.