ABSTRACT
The maximum longevity in birds is known to range from 4 years for blue jays (
Cyanocitta cristata
) to 64 years for macaws (
Ara macao
). The longevity of birds is somewhat surprising, since they exhibit many traits that should render them more susceptible to the degenerative processes of aging. These traits have been reviewed
and include (1) metabolic rates as much as 2 to 2.5 times greater than those
of mammals of similar body size, (2) blood sugar levels typically two to six times higher than those of mammals, and (3) body temperatures about 3
°
C higher than mammals. Each of these factors should expose them to a higher rate of free oxygen radical production and accelerate the formation of Maillard products (Figure 29.1). Without special protective mechanisms against the potential for oxidative damage, birds should be comparatively short lived and age more rapidly than mammals. However, it has been reported that avian species have higher levels of circulating antioxidants (
α
-tocopherols, carotenoids, and uric acids) compared with comparably sized mammals.
