美国自然历史博物馆和普林斯顿大学的研究人员发现，恐龙尽管能够进化成巨型生物，却从未占据极小的生态位。[1]已知最小的非鸟类恐龙体重约450克，比蜜蜂蜂鸟重超200倍。[1]相比之下，现代哺乳动物中约75%的物种和90%的鸟类物种都小于已知最小恐龙。[1]
研究人员采用数学模型来分析这一现象，结果显示该模型能够解释哺乳动物、鸟类和龟类的体型范围，但无法仅通过生理学因素解释非鸟类恐龙保持相对较大体型的原因。[1]研究认为，早期小型哺乳动物与恐龙的生态竞争可能阻止了恐龙占据鼠类和麻雀大小的生态位。[1]
普林斯顿大学的罗杰·本森指出："恐龙的祖先可以很小，现存恐龙后代鸟类可以很小，但恐龙本身似乎被禁止变小。"[1]这项研究于2026年8月9日发表在《进化》期刊上，对理解恐龙和现代生物多样性的进化具有重要意义。[1]
Researchers from the American Museum of Natural History and Princeton University have used mathematical modeling to investigate why dinosaurs never evolved into extremely small body sizes, a pattern that cannot be explained by physiology alone.[1] The smallest known non-avian dinosaurs weighed approximately 450 grams, making them over 200 times heavier than the bee hummingbird at 1.75 grams.[1] In contrast, roughly 75 percent of modern mammal species and 90 percent of bird species are smaller than the smallest known dinosaurs.[1]
The research team discovered that while mathematical models can successfully explain the body size ranges observed in mammals, birds, and turtles, they fail to account for why non-avian dinosaurs remained relatively large throughout their history.[1] According to Roger Benson, one of the researchers, "Dinosaurs' ancestors could be small, and living dinosaur descendants, birds, can be small, but dinosaurs themselves seem to have been prohibited from becoming small."[1] The team's findings suggest that ecological competition from early small mammals may have prevented dinosaurs from occupying ecological niches inhabited by creatures the size of rodents and sparrows, a phenomenon with significant implications for understanding both dinosaur evolution and modern biodiversity.[1] The study was published in the journal Evolution on August 9, 2026.[1]