They are vegetarians, 它们是素食者

131. And the frontier between these two very different worlds
     而这两个不同世界的交界处
132. is the home of one of the strangest of reptiles.
     生活着最奇异的爬行动物
133. Seagoing iguanas.
     海鬣蜥
134. They are vegetarians,
     它们是素食者
135. but since there's little food for them on the land,
     但由于岛上没有能吃的食物
136. marine iguanas graze on the sea floor.
     所以海鬣蜥以海底的植物为食
137. A big male like this one can dive to 30 metres
     这种体型的雄性海鬣蜥可潜到水下三十米

来自《行星地球 第二季 第一集 Planet Earth S02E01 岛屿》第 134 行