Wikipedia:Vestigial structures are often called vestigial organs, although many of them are not actually organs. These are typically in a degenerate, atrophied, or rudimentary condition,[1] and tend to be much more variable than similar parts. Although structures usually called "vestigial" are largely or entirely functionless, a vestigial structure may retain lesser functions or develop minor new ones.[2] However, care must be taken not to apply the lable of vestigiality to exaptations, in which a structure originally used for one purpose is modified for a new one. For example, the wings of penguin would not be vestigial, as they have been modified for a substantial new purpose (underwater locomotion), while those of an emu would be, as they have no major purpose anymore (not even for display as in ostriches).