All organisms age, in the search of the universal mechanisms of aging Barja analyzed results obtained with various species of mammals and birds and concluded that only two known factors correlate in the right sense (inversely) with animal longevity in vertebrates: the long life span is associated with (a) low rates of mitochondrial reactive oxygen species production, and (b) low degree of fatty acid polyunsaturation of cellular membranes including the mitochondrial ones [Barja (2014) Prog Mol Biol Transl Sci. 127:1-27].