Wolf Evolution and Taxonomy

Abstract
The numbers of the grey wolf (Canis lupus) in Europe have declined significantly and nowadays its range is fragmented. Many authors publish data about skull size but they are based on different measurements. Our study aims to unify these data based on the common parameters. Using “Google search” and books in English, Russian and Bulgarian, we have found information about cranium investigations of grey wolf populations in Europe and Asia. Common cranial parameters were extracted and presented separately for both sexes. The current study gathers already available information from Europe and Asia, adding the latest data from Bulgaria. Thus, our paper provides an opportunity for future craniological studies of geographic polymorphism in this species.

The gray wolf, Canis lupus, once inhabited much of the northern hemisphere worldwide; however, persecution drove its populations almost to extinction. In North America, diverse conservation programs have been implemented in the last decades to recover its populations in the wild, many of them guided by the historical distribution of the gray wolf subspecies. Over time, several authors have proposed different subspecies classifications. Nevertheless, most of them are mutually inconsistent regarding the number and distribution of subspecies, creating controversy when implementing conservation programs. This study used niche-based distribution models and cluster analysis to explore the bioclimatic profiles of C. lupus across North America and compare them with different subspecies classifications to identify environmental correlatives that support the proposed designations. Our cluster analysis results indicate that the optimal number of climatic groups was five, designated as Northern, Eastern, Western, Coastal, and Southern groups, with transitional overlap boundaries located at their peripheries, indicating climatic gradients between them and supporting the idea of intergrading zones. The geographic ranges of these groups mismatched to a different extent with all subspecies delimitations. In general, the boundaries of putative subspecies did not match the climatic patterns of North America. Our results may contribute to the recovery programs underway for this carnivore by identifying suitable areas for the release of individuals from specific lineages. New approaches to characterizing the intraspecific variation of the gray wolf should include all evidence available, including genetic, morphological, and ecological information.

Abstract
Dogs were domesticated at least once from a yet-unidentified wolf population at least ~15,000 y ago. However, how domestication took place is a topic of ongoing debate, and the ability of human groups to manage wolves in their communities during early stages of domestication is poorly understood. Here, we report multiproxy data from two canids excavated from Late Neolithic and Bronze Age contexts in the Stora Förvar cave on the island of Stora Karlsö in the Baltic Sea. The island is small (2.5 sq km) and, like the neighboring island of Gotland, carries no endemic populations of terrestrial mammals. Instead, the current consensus is that human introductions account for some mammal fauna on Gotland, and for the majority of that on Stora Karlsö. Genome-wide data show that the two canids have ancestry indistinguishable from Eurasian wolves, with no shared ancestry with domestic dogs of the Canis familiaris lineage. Their genome-wide heterozygosity is lower than that observed in 72 previously published ancient wolf genomes, and instead comparable to dogs. Stable isotope data (δ13C and δ15N) reveals a diet rich in marine protein, which is consistent with habitation alongside the human groups who used Stora Karlsö as a seal-hunting, fowling, and sea fishing station, and in the Bronze Age probably also for grazing. Skeletal size is at the lower end of wolf variability, and one individual shows advanced pathology consistent with reduced mobility. While other scenarios are possible, a parsimonious explanation is that these wolves were brought to the island by humans and were possibly under human control.

We investigate if and how diets of gray wolves from the Yukon Territory, Canada, have changed from the Pleistocene (>52.8 ka BP to 26.5 ka BP [±170 y BP]) to the recent Holocene (1960s) using dental microwear analysis of carnassial teeth and stable isotope analyses of carbonates (δ13CCO3 and δ18OCO3) and collagen (δ13Ccol and δ15Ncol) from bone. We find that dental microwear patterns are similar between the Pleistocene and Holocene specimens, indicating that there has been no change in carcass utilization behaviours, where flesh, not bone, is primarily consumed. Based on minimal changes in δ13CCO3 and δ13Ccol values, we find that, over thousands of years, Yukon gray wolves have remained generalist predators feeding upon several large ungulate species. Interestingly, δ15Ncol values suggest that the extinction of megafaunal species at ~11.7 Ka induced a shift from a diet comprised primarily of horse (Equus sp.) to one based on cervids (i.e. moose and caribou). Survival of large-bodied cervids, such as caribou (Rangifer tarandus), was likely key to wolf survival. Although gray wolves survived the end Pleistocene megafauna extinction and demonstrate a degree of ecological flexibility, we suggest that failure to preserve major elements of their current niche (e.G. caribou) may result in continued population declines, especially in the face of increasing anthropogenic influences.