Abstract This paper proposes the innovative concept of lexical niche to analyze the ecology of vocabulary from an ecolinguistic perspective. Through the examination of niche breadth and overlap, we quantitatively assess the vitality and competition of six typical Chinese eating verbs: shi (食), fan (饭), can (餐), dan (啖), ru (茹), and chi (吃). The analysis reveals their diachronic evolution in the history of the Chinese language (temporal niche), their synchronic distribution in Chinese dialects (spatial niche), and their verb-object collocation (functional niche). The findings indicate the following: (1) Shi, fan, can, dan, and ru originated in Early Old Chinese, while chi emerged in Late Old Chinese. (2) The niche breadths of the six eating verbs are as follows: 2.585, −2.391, −2.242, −0.108, −1.734, and 3.889, respectively. Chi demonstrates the highest vitality, followed by shi; fan, can, dan, and ru exhibit extremely low vitality. (3) Shi originated in the Pre-Qin dynasty, serving as the dominant eating verb in ancient times with robust competition. However, in modern times, it has evolved into a morpheme for compound words, displaying weak sustainability. Chi, born in the Han dynasty, replaced shi as the dominant eating verb by the late Tang dynasty, establishing itself as the most competitive verb to date, characterized by strong sustainability.