Felidae is the generic term for all big and small cats. It is a subdivision of the mammals. Therefore in biological terms, 'Felidae' is the name of the family of the tiger. A family contains several species with a number of common characteristics.
The felidae are often subdivided into two other subfamilies: the big cats (Pantherinae) and the small cats (Felinae).
Between the big and the small cats there are, except for their dimensions, several other differences. The more important onces are:
The Pantherinae, the subfamily of the big cats, can be subdivided again in some (biological) genera. Two members of the same genus have even more characteristics in common than two members of the same family.
The big cats exist out of 3 different genera: