How long ago did the dog and wolf separate from their ancestor?

Dates for the most recent common ancestor (MRCA) for dogs and wolves are remarkable recent. When Stan Olsen (1983) wrote his classic work on domestic dog fossils (1983) he noted the oldest known remains were from Palegawra Cave in northeastern Iraq with an estimated age of 12 thousand years before present (YBP).

But subsequent evidence suggests that dogs split from wolves much latter than those fossils would imply. Deep in Chauvet cave, in France, Garcia (2005) found a track of footprints from a large canid associated with one of a child. Torch wipes made by this child were dated at about 26,000 YBP. Based on the short length of medial fingers in the footprints the canid track was interpreted as being made by a large dog.

Genetic data also suggests that the dogs originated prior to the often cited 15,000 YBP. Ostrander and Wayne (2005) report that mitochondrial DNA (mtDNA) sequence analysis shed some light on the location of dog domestication as well as the number of founding matralines. They found dog sequences in at least four distinct clades, suggesting a single origin event and at least three other origination or interbreeding events. They also found nucleotide diversity high, implying an origin date of 135 to 40 thousand YBP. And Ostrander and Wayne (2005) suggests dogs may have had a long prehistory when they were not phenotypically distinct from wolf progenitors. Therefore early dogs may not have been recognized as domesticated in the archaeological record prior to 15,000 YBP because of their physical similarity to gray wolves.

However, a group of morphologically distinct canids hypothesized to be early domesticated dogs have been identified by Germonpré et al., (2009, 2012). Seven complete large canid skulls and 26 skull fragments from the Gravettian Předmostí site in the Czech Republic were examined, three skulls were identified as European Palaeolithic dogs, characterized by short skulls, short snouts, wide palates and braincases, and even-sized carnassials. The presence of dogs at Předmostí supports the hypothesis that domestication of dogs began long before the Late Glacial. One of the skulls was identified as a Pleistocene wolf, three other skulls could not be assigned to a group. Furthermore, at Předmostí, several human modifications of the skulls and canines hint at a specific relationship between humans and large canids.

While this has been controversial (see Crockford and Kuzmin, 2012), the evidence continues to mount supporting a much older origin of dogs. Druzhkova et al. (2013) provide molecular evidence that the 33,000-year old Pleistocene dog from Altai has a unique haplotype and the Altai dog is more closely related to modern dogs and prehistoric New World canids than it is to extant wolves.

In a forthcoming article in Quaternary International Pat Shipman of Pennsylvania State University asks the question, how do you kill 86 mammoths. The author examines a series of Eurasian archaeological sites formed between about 40 and 15 thousand years ago that feature unusually large numbers of mammoth remains with abundant artifacts and, often, mammoth bone dwellings. 

Since the late 19th century, archaeological sites dominated by mammoth remains have been a focus for research. How the bones of large numbers of mammoths, ranging from a minimum number of five individuals to hundreds of individuals, were deposited in one place remains an un-answered question. And, despite previous investigation, the cause of death of mammoths in these sites has remained controversial.

Two predominate hypotheses have been used to explain these megasites (a reference to the large number of mammoth remains): (1) the mammoths died natural deaths which were subsequently scavenged by humans; (2) or that specialized human hunting resulted in the deaths of the mammoths. Questions about collection and excavation techniques pose challenges for synthesizing the information, but the wealth of material has produced numerous published zooarchaeological analyses of the sites, including number of non-mammoth species represented, minimum numbers of mammoths at each site, mammoth age at death, and mammoth age profiles from individual sites.

All of these mammoth megasites are dated after the appearance of modern humans in Eurasia. These unusual sites are of interest given the obvious successes of the humans that made them. But, also because of the large number of individual mammoths and the scarcity of carnivore tooth marks and gnawing.  The evidence suggest the mammoth hunters had invented a new ability to retain and control the mammoth carcasses – protecting all of that valuable protein from scavengers.

Age profiles of mammoths at the megasites differ statistically at the p < 0.01 level from age profiles of African elephant populations that died of either attritional or catastrophic causes. However, age profiles from some mammoth sites exhibit a chain of linked resemblances with each other through time and space, again suggesting hunter behavioral and technological innovation.

The megasites Shipman analyzed are spread across most of the Eurasian continent and over a substantial time span. The introduction and spread of complex projectile weaponry by modern humans was probably important in producing the abrupt changes in assemblages associated with hominins that started about 45,000 YBP. Previous authors observed that reduced weight projectile weapons are a “niche-broadening technology” because they are easily carried, retain energy longer in flight, and they reduce the risk of injury when hunting dangerous animals or in combat when fighting other people. Thus early modern humans may have broaden their ecological niche. The reduced weight projectile weapons transforms the hunters from ambush predators (as Neanderthals were) to being long-distance hunters. Shipman also suggests a second advance which occurred during MIS 3 (marine isotope stage 3, which started 57,000 YBP) may have enhanced the advantages of reduced weight projectile weapon technology - a quasi-domesticated large canids willing to work cooperatively with humans.

Shipman (2014) hypothesize that this innovation may have been facilitated by an early attempt to domesticate dogs, as indicated by a group of genetically and morphologically distinct large canids which first appear in archaeological sites at about 32,000 YBP.

Thus at the moment it would appear that the MRCA of dogs and wolves is indeed much older than 15,000 YBP. It also appears that dogs, were co-operating with humans at least 32,000 YPB. But did humans domesticate the dog, or did dogs evolve from wolves all on their own?

Citations

Crockford, S. J., & Kuzmin, Y. V. (2012). Comments on Germonpré et al., Journal of Archaeological Science 36, 2009 “Fossil dogs and wolves from Palaeolithic sites in Belgium, the Ukraine and Russia: osteometry, ancient DNA and stable isotopes”, and Germonpré, Lázkičková-Galetová, and Sablin, Journal of Archaeological Science 39, 2012 “Palaeolithic dog skulls at the Gravettian Předmostí site, the Czech Republic”. Journal of Archaeological Science, 39(8), 2797-2801.

Druzhkova AS, Thalmann O, Trifonov VA, Leonard JA, Vorobieva NV, et al. (2013) Ancient DNA Analysis Affirms the Canid from Altai as a Primitive Dog. PLoS ONE 8(3): e57754. doi:10.1371/journal.pone.0057754.

Garcia, M.A., 2005. Ichnologie ge’ne’ rale de la grotte Chauvet. Bulletin de la Socie’ te’ pre’ historique francaise 102, 103–108.

Germonpré, M., Sablin, M. V., Stevens, R. E., Hedges, R. E., Hofreiter, M., Stiller, M., & Després, V. R. (2009). Fossil dogs and wolves from Palaeolithic sites in Belgium, the Ukraine and Russia: osteometry, ancient DNA and stable isotopes. Journal of Archaeological Science, 36: 473-490.

Germonpré, M., Lázničková-Galetová, M., & Sablin, M. V. (2012). Palaeolithic dog skulls at the Gravettian Předmostí site, the Czech Republic. Journal of Archaeological Science, 39(1), 184-202.

Kolosov, P. N. (2014). Primitive Mammoth Hunters and the Earliest Breed of Dog. Natural Resources, 2014.

Olsen, S. J. (1985). Origins of the domestic dog: the fossil record. University of Arizona Press, Tucson. 117 pp.

Ostrander, E. A., & Wayne, R. K. (2005). The canine genome. Genome research, 15(12), 1706-1716.

Shipman, P. (in press, 2014). How do you kill 86 mammoths? Taphonomic investigations of mammoth megasites. Quaternary International.