Our combination of molars, canines, and incisors help us to consume a diverse and omnivorous diet, unlike many other animals. Fannin explained that anthropologists often discuss hominin behavioral and morphological changes as if they evolved in tandem with one another. However, these changing palettes came at least 700,000 years before their teeth and digestive systems optimized for the vegetation. Then, about 2.3 million years ago, hominin teeth began exhibiting significantly smaller amounts of oxygen and carbon isotopes. According to researchers, this implies that the era’s human ancestor—Homo rudolfensis—lessened their grass intake for oxygen-depleted water.