The skull in lateral and ventral view (scale bar 10 mm)
The orbital angle
Some time ago, in a forest near one village in Slovakia, I’ve found this skull. After looking at it for a bit, and drawing it, I suppose, that it most likely belongs to a dog, with a wolf-like head, perhaps a german shepherd, wolfdog, some northern breed or a mongrel of them… But not totally excluding the posibility of a wolf.
The lenght of the skull is a little smaller (21,1 cm) than that, what I found to be the average for the wolf as a species (23 – 28 cm), althought I’m not aware of the local wolves’ average sizes. The individual was already mature and probably not the youngest, since the teeth (P4, M1, M2) show large wear.
One characteristic commonly used to distinguish between wolves and the first domesticated dogs, is the orbital angle (shown in the picture above). The sharper the angle is the more “wolf-like” the head becomes. Some disagreement exists however, because apparently it’s a very variable feature, that must be taken with a grain of salt. I applied it to my skull, and it falls within the lower edge of a domesticated dog standards and higher edge of wolf’s.
As this is a very quick overview, and I’m an amateur on Canis skull morphology, feel free to refer to anything I missed out on!
I bet a lot of you are familiar with the Dire wolf (Aenocyon dirus). The biggest canine (member of caninae) ever, that roamed North america and preyed on the large megafauna of the Pleistocene Americas. Althought it wasn’t really closely related to the typical wolf, and hence it wouldn’t even look like one. What can be overlooked however, is that, during these times, the modern wolves (Canis lupus) not only existed in large numbers, but also were much more diverse, with very large and robustly built morphs extending as far north as the Beringia.
Beringia is usually devided to western (Russian side) and eastern (Alaskan side) part. Sea levels were much lower then, which meant that the bridge between the continents was connected. This article mostly focuses on the eastern part (Fairbanks area) but not only. During the late Pleistocene, (here focusing on the last 100,000 years) Beringia was nothing like it’s today. At that time, a mosaic of high productive steppe-tundra existed, which supported numerous species of herbs, grasses, lichens and even shrubs and trees… It was in this environment where a handful of megafaunal species could be found, from herbivores: mammoth (Mammuthus primigenius), bison (Bison priscus), caribou (Rangifer tarandus), woodland muskox (now considered Bootherium bombifrons), the wild yak (Bos mutus) and Yukon horse (Equus lambei) and on the western (siberian) side also the Lena horse (Equus lenensis) existed, among others. The guild of the largest carnivores was occupied by the now-extinct wolf ecomorph (Canis lupus), giant short-faced bear (Arctodus simus) Brown bear (Ursus arctos), cave and/or american lion (Panthera spelaea/atrox) and the scimitar cat (Homotheriumserum).
Two beringian wolf individuals with different color variations (typical grey-toned and lighter arctic form) with one of their prey items, the Yukon horse. Human sillhouette is ~1.8 meters tall.
Althought this environment was always more or less very cold, several climatic changes are recorded, with the Last Glacial Maximum (roughly somewhere between 26,000 to 18,000 years before present) being very prominent one. This means that overtime a lot of smaller changes in the faunal communities existed. From stable carbon and nitrogen isotope and radiocarbon analysis, the diets of species can be inferred. The beringian wolf was both an active predator and a scavenger, which enabled it to survive even the harshest periods. These wolf are considered to be horse/bison generalists, and competed for the same resources with other predators such as the scimitar cat (Homotherium serum). From the eastern Beringia (Fairbanks area), interestingly, during the whole Late Pleistocene only the wolf seemed to persisted the whole time, while for example felids (scimitar cat and lion) were only scarcely present when short-faced bears occupied the land (40,000 to 20,500 years before present). For comparison the latter seems to have been a caribou specialist, althought it is reasonable to assume that the specializations of different carnivores cannot be so stricly defined (if a predator was starving it would eat anything it stumbled upon).
The mammoth steppe was a very vast habitat in both area and time, which stretched through whole Eurasia and Alaska, so surely there must had been a lot of different local interactions and dynamics both between the predators themselves and their prey.
This environment produced, compared to its modern counterparts, an extreme form of the wolf (Canis lupus), that was adapted to scavenging and hunting on the large herbivores present. It tended to posses short, broad palates and larger carnassials relative to the skull size, altogether indicating adaptations typical for bonecraking behaviour, that would require the ability to produce large bite forces. Perhaps one of its good modern analogues is the Spotted hyaena of the african savannahs.
The beringian wolf
According to the genetic evidence the beringian wolves (even those found on the American side) were not related to the modern North American and Eurasian wolves, and most likely represent a lineage, now extinct, that once stretched through the whole Eurasia. For instance, several pre-LGM (Last Glacial Maximum) wolf specimens from Ukraine, Chzechia and Altai (Altai dog) region show genetic (mitochondrial DNA haplotype) similarities to some beringian wolves, which is opposed to the modern populations which show no relatedness.
Despite before-mentioned differences, in nature, it would look like a normal wolf. Here, two possible color variations are shown based on the environment (the standard grey-toned and a lighter arctic form). As one of their potential prey items, I drew the Yukon horse, which (based on one partial carcass) would be in life a small (~1.2 meters tall) horse closely resembling the tarpan and przewalski’s horse, perhaps with a thicker fur adapted to colder climates.
During the Early Pleistocene (roughly 1.3 million years ago), East Asia was home to a number of different large-bodied canines, including genera such as: Canis, Xenocyon, Cuon and Sinicuon. However, the exact taxonomic position of every specimen found is not completely clear…
Recently described partial skeleton (in 2012), with most of the vertebral column and rib cage missing, is an important one. It’s pretty obvious that this specimen is a member of the genus Canis, based on the material, it was assigned to Canis chihliensis, a species unique to China. While being much smaller in size than the modern wolf (Canis lupus), it also appears to be more primitive, thanks to less robust built of the limbs. The assumption of primitivness is based on the fact that canines (Canis, Cuon and Lycaon), in general tend to evolve to become more heavily built and adapted to hunting prey larger than themselves. Additionally, different specimen of C. chihliensis show signs of serious tooth wear and breakage as well as tibial fracture. All the trauma and infections seen in this canid are a good indicator for bone-crushing behaviour and living in packs (the specimen with a broken leg has a much higher chance of healing and surviving when it is cared for in a group), which is linked to hunting large prey.
This canid shared its habitat with numerous other ice age mammals, such as the hyaena Pachycrocutasp., pantherine cats, Nihewan wooly rhinoceros (Coelodonta nihowanensis), Steppe mammoth (Mammuthus trogontherii), the deer Eucladocerosboulei, horses and more…
