狼吃羊是常识。澳大利亚的袋狼因为人类认为它们会吃羊而被大规模捕杀，随后灭绝。一项最新研究为袋狼“昭雪”：袋狼可能并不具备吃羊的能力，而是以一些更小的动物为食。
袋狼曾经生活在澳大利亚的塔斯马尼亚岛等地，它们和袋鼠一样是有袋动物，外形与狼相似。因为身上有类似老虎的斑纹，袋狼又被称作塔斯马尼亚虎。袋狼是肉食动物，因此来到澳大利亚的欧洲移民认为它们会袭击羊群，曾悬赏大规模捕杀袋狼，造成其数量锐减。加上其他因素的影响，袋狼在上世纪30年代灭绝。
不过英国伦敦动物学会主办的《动物学期刊》（Journal of Zoology ）刊登一项最新研究报告说，人类很可能冤枉了袋狼。
澳大利亚新南威尔士大学的研究人员对保存下来的袋狼头骨进行了分析，利用计算机模型分析了它们在咬合和用嘴撕扯方面的力学特点，发现袋狼的下颚比较脆弱。在比较其他一些肉食动物的头骨后，研究人员认为袋狼难以捕食像羊这么大的猎物。
研究人员斯蒂芬•弗罗说，通过比较袋狼与其他一些动物的头骨特点，可以相当肯定地认为，袋狼的捕食对象是一些较小的动物，比如小袋鼠和负鼠。
他说，袋狼捕猎范围相对狭窄，也使得它们更易受生态系统变化的影响。欧洲移民来到澳大利亚后，一方面悬赏捕杀袋狼，另一方面也改变了当地的生态系统，这些因素共同导致了袋狼的灭绝。
生物探索推荐英文论文摘要：
Abstract
Extinction risk varies across species and is influenced by key ecological parameters, such as diet specialization. For predictive conservation science to be effective, we need to understand extinction risk factors that may have implicated recent species extinctions. Diet and feeding behaviour of the large extinct marsupial carnivore Thylacinus cynocephalus or thylacine have long been debated. Improved understanding of the ***'s biomechanical performance and its limitations in a comparative context may yield important insights. Here, we use three-dimensional (3D) finite element analysis to assess aspects of biomechanical performance in the *** of T. cynocephalus relative to those of two extant marsupial carnivores with known diets that occurred sympatrically with T. cynocephalus: the Tasmanian devil, Sarcophilus harrisii, and spotted-tailed quoll, Dasyurus maculatus. Together, these three species comprised the large mammalian carnivore guild in Tasmania at the time of European settlement. The bone-cracking S. harrisii produced high bite forces for its size as expected, but the stresses induced were surprisingly high. A higher proportion of cancellous bone in the *** of this osteophage may act to absorb shock but decrease rigidity and hence raise stress. A relatively high bite force and rigid *** characterized D. maculatus, which may allow them to target prey of variable sizes. Compared with S. harrisii and D. maculatus, we found that the *** of T. cynocephalus was least well adapted to withstand forces driven solely by its jaw-closing musculature, as well as to simulations of struggling prey. Our findings suggest that T. cynocephalus likely consumed smaller prey relative to its size, which may have had implications for their survival.
英文论文全文阅读：新研究称澳洲袋狼可能不吃羊.pdf
