Indigenous communities on the Northern Great Plains of North America commonly kept dogs as domestic animals. Historical records and previous archaeological research indicate that many of these dogs were large-bodied animals. Both data sources also suggest that wolf-dog interbreeding was common and in part occurred as a means of producing large dogs for use in transport. However, nearly all previous studies of large canid remains on the Great Plains rely on traditional morphometrics, a method that can conflate shape differences with size differences due to isometry. Geometric morphometrics, a method that can factor out such scaling effects, is applied in this study to Late Holocene large canid remains from two non-archaeological locations on the plains of Alberta, Canada. Our results indicate the presence of both dogs and wolves, with many of the wolves experiencing extreme tooth wear and loss and having small body sizes. We argue that wolves on the plains were far more variable than presently recognized and that such smaller wolves are likely to be confused with early generation hybrid animals when studied with traditional morphometrics. Differences in wolf and dog reproductive biology and behaviour likely made wolf-dog introgression rare rather than common. The use of advanced methodologies such as geometric morphometrics is needed to more confidently identify ancient North American canid remains. However, such methodologies must rely upon comprehensive comparative datasets that account for past variability in regional canids. Traditional morphometrics will continue to have an important role in the study of North American canid remains due to the fragmentary nature of most archaeological specimens. Such methods will be most effectively used in combination with other methodologies.

北美北部大平原上的土著社区通常将狗作为家畜饲养。历史记录和先前的考古研究表明，这些狗中有许多是体型较大的动物。这两个数据来源还表明，狼犬杂交很常见，并且部分是作为生产大型犬用于运输的一种手段。然而，几乎所有先前对大平原上大型犬科动物遗骸的研究都依赖于传统的形态测量学，这种方法可以将形状差异与等距引起的尺寸差异混为一谈。几何形态测量学是一种可以排除这种比例效应的方法，在这项研究中应用于来自加拿大艾伯塔省平原上两个非考古地点的晚全新世大型犬科动物遗骸。我们的结果表明狗和狼的存在，许多狼的牙齿磨损严重，体型较小。我们认为，平原上的狼比目前公认的变异性要大得多，当用传统的形态测量学研究时，这些较小的狼很可能与早期杂交动物混淆。狼和狗的生殖生物学和行为的差异可能使狼狗基因渗入变得罕见而不是普遍。需要使用几何形态计量学等先进方法来更自信地识别古代北美犬类遗骸。然而，这些方法必须依赖于综合比较数据集，这些数据集解释了区域犬科动物过去的变异性。由于大多数考古标本的碎片性，传统形态测量学将继续在北美犬科动物遗骸的研究中发挥重要作用。这些方法将最有效地与其他方法结合使用。