Hadrosauridae, consisting of two subfamilies (Hadrosaurinae and Lambeosaurinae), is a successful herbivorous dinosaur group that established a high taxonomic diversity and a cosmopolitan biogeographic distribution during the Late Cretaceous. While its success is often attributed to a highly specialized oral processing system, the foraging strategy of this group remains unclear. This study focuses on two critical factors in foraging strategy, food selectivity and locomotor ecology, in these hadrosaurid subfamilies. Three-dimensional beak shapes and limb segment proportions are used as the proxies for food selectivity and locomotor ecology, respectively. The beak shape analysis demonstrates trends of anteriorly acute beaks in hadrosaurines and anteriorly wide beaks in lambeosaurines. The limb segment proportion analysis shows short proximal limb segments in hadrosaurines and long proximal limb segments in lambeosaurines. These results suggest that hadrosaurines preferred selective consumption of high-quality food with energy-inefficient locomotor ecology, while lambeosaurines preferred mass consumption of low-quality food with energy-efficient locomotion and that differences in foraging strategy might have enhanced dietary niche partitioning in the subfamily level of hadrosaurids. In addition, this study tests a relationship between limb proportions and habitat environments in hadrosaurids. We demonstrate that hadrosaurids from the coastal environments have shorter forelimbs than those from the terrestrial environment. Since short forelimbs are better suited for temporal bipedalism than long forelimbs, the limb proportion difference may indicate adaptations to different feeding heights, possibly due to different regional vegetations.

鸭嘴龙科由两个亚科（鸭嘴龙科和蓝龙科）组成，是一个成功的草食性恐龙群，在白垩纪晚期建立了高度的分类多样性和世界性的生物地理分布。虽然它的成功通常归功于高度专业化的口腔处理系统，但该群体的觅食策略仍不清楚。本研究侧重于这些鸭嘴龙亚科中觅食策略的两个关键因素，食物选择性和运动生态学。三维喙形状和肢体节段比例分别用作食物选择性和运动生态学的代理。喙形分析显示了鸭嘴龙科前部锐喙和羔羊科前部宽喙的趋势。肢体节段比例分析显示鸭嘴龙科的近端肢体短节和兰氏龙科的长近节肢体节段。这些结果表明，鸭嘴龙类更喜欢有选择地食用具有低能效运动生态的高质量食物，而羊角龙类更喜欢大量食用具有节能运动的低质量食物，并且觅食策略的差异可能增强了亚科的饮食生态位划分鸭嘴龙类的水平。此外，这项研究还测试了鸭嘴龙科动物肢体比例与栖息环境之间的关系。我们证明来自沿海环境的鸭嘴龙科动物的前肢比来自陆地环境的鸭嘴龙科动物的前肢短。由于短前肢比长前肢更适合双足行走，