Anaerobic glycolysis is a process in which energy is
produced, without oxygen, through the breakdown of
muscle glycogen into lactic acid and adenosine tri-
phosphate (ATP), the energy provider. The amount
of energy that can be produced anaerobically is a
function of the amount of glycogen present—in all
vertebrates about 0.5 percent of their muscles'wet
weight. Thus the anaerobic energy reserves of a verte-
brate are proportional to the size of the animal. If, for
example, some predators had attacked a 100-ton
dinosaur, normally torpid, the dinosaur would have
been able to generate almost instantaneously, via
anaerobic glycolysis, the energy of 3,000 humans at
maximum oxidative metabolic energy production.