Field of Science

The Wolf in Time

Black-backed jackal pup Canis mesomelas, photographed by Blake Matheson.

The dogs of the genus Canis include some of the most familiar of all mammals: the wolf Canis lupus, the coyote C. latrans, and of course the domestic dog Canis familiaris. I have already discussed in an earlier post how these three, together with the golden (Canis aureus) and the Simien (C. simensis) jackals, form a cluster of closely related species (that I'll refer to as the 'wolf group') that are not always clearly separated. Today, I'll take things a bit further and look at the fossil history of the genus Canis.

Coyote Canis latrans, from Ryan Photographic.

The earliest taxa assigned to the genus Canis are known from the late Miocene, about six million years ago (Tedford et al. 2009). Early Canis have been identified in both Europe (C. cipio) and North America (C. ferox), though there is some uncertainty about whether the European C. cipio should be treated as Canis or assigned to the related, slightly earlier fossil genus Eucyon. Whatever the case, it doesn't appear to have been long before Canis populations were well and truly established on both continents. The North American Canis ferox was, as far as I can tell, probably not dissimilar to a modern coyote in appearance, and early Canis species probably also resembled coyotes in being fairly generalist predators. In the evolutionary analysis by Tedford et al. (2009), C. ferox was suggested to have begat C. lepophagus at the beginning of the Pliocene, which in turn begat two lineages: one leading to the modern wolf group, the other leading to three North American Plio-Pleistocene species (C. thooides, C. feneus and C. cedazoensis) that were smaller than their ancestor and probably similar in appearance to modern jackals. It is somewhat unfortunate that Tedford et al.'s analysis did not include the African side-striped (C. adustus) and black-backed (C. mesomelas) jackals, which molecular and morphological analyses have generally agreed lie outside the wolf group. Biogeography alone suggests that the North American 'jackals' were probably convergent rather than directly related to the modern African species, but it would be nice to know.

Mounted skeleton of dire wolf Canis dirus, from lora_313. This species probably weighed between 50 to 80 kg, which is comparable in size to a very large dog such as a bullmastiff or great dane.

The modern wolf group diversified in the late Pliocene, including a number of fossil species as well as the modern. The rate of diversification and spread of wolf-group Canis was such that palaeontologists refer to their appearance in the fossil record as the 'wolf event', and use it as a marker of the development of the colder tundra climate of the Pleistocene ice ages. Higher diversity in Eurasia suggests that it was probably the centre of diversification, with North American species derived from repeated colonisation. Significant among these was the relatively large C. armbrusteri, a close relative of the grey wolf C. lupus. Canis armbrusteri is notable as the probable ancestor of the late Pleistocene dire wolf C. dirus, made famous by its appearances in the works of Robert E. Howard* and similar authors. As well as being a dominant predator in North America, the dire wolf spread into northwestern South America. A similar large Canis species, C. nehringi, is also known from the same time in Argentina, but the analysis of South American canids by Prevosti (2010) was unable to clearly determine whether C. nehringi was a southern relative of C. dirus or a convergent relative of the Xenocyon lineage.

*A man who spent far too much time thinking about oiled chests if ever there was one.

Dholes Cuon alpinus, from Rajnish Pradhan.

Xenocyon is itself relevant to the history of Canis: first appearing in the late Pliocene, Xenocyon lycaonoides is probably the ancestor of the modern African hunting dog Lycaon pictus and the Asian dhole Cuon alpinus, forming a hypercarnivorous lineage specialised for collaborative hunting of large prey. Phylogenetic analyses of modern taxa have varied as to whether Lycaon and Cuon are the sister group of modern Canis, or whether they are in fact more closely related to the wolf group than are C. adustus or C. mesomelas, rendering Canis paraphyletic. Removal of the latter two species from Canis into separate genera as Schaeffia adusta and Lupulella mesomelas to preserve monophyly has been suggested, but almost universally ignored (as well as failing to resolve the status of the non-wolf-group fossil Canis species). Tedford et al. (2009) even nested the Xenocyon lineage within the wolf group itself, as sister to the Canis lupus-C. dirus group, but one might suspect the influence of convergences to large size and hypercarnivory. Prevosti (2010) placed Lycaon and Cuon in a more standard position just outside the wolf group, but did not consider as many fossil Canis species as Tedford et al.

Remains of Cynotherium sardous (plus some smaller mammal), from here.

The Xenocyon lineage was undoubtedly Eurasian in origin, but the primarily Eurasian X. lycaonoides did spread into northern North America, and a second species X. texanus was found in the Pleistocene of (surprisingly) Texas. The modern dhole Cuon alpinus was also present in North America in the latest Pleistocene, with remains of at least four individuals found in a cave in northeastern Mexico, as well as being found in Europe (Tedford et al. 2009). Also a member of the Xenocyon lineage was the Pleistocene Cynotherium sardous, found on the Mediterranean islands of Sardinia and Corsica (which were a single island when the Mediterranean sea level was lower). Though descended from hypercarnivorous ancestors, Cynotherium became adapted in its island habitat to hunting smaller prey (such as the Sardinian lagomorph Prolagus sardus). Though it retained the simplified dentition of a hypercarnivore, it became smaller and the skull became less reinforced, as befits an animal no longer wrestling down large ungulates (Lyras et al. 2006).


Lyras, G. A., A. A. E. Van Der Geer, M. D. Dermitzakis & J. De Vos. 2006. Cynotherium sardous, an insular canid (Mammalia: Carnivora) from the Pleistocene of Sardinia (Italy), and its origin. Journal of Vertebrate Paleontology 26 (3): 735-745.

Prevosti, F. J. 2010. Phylogeny of the large extinct South American canids (Mammalia, Carnivora, Canidae) using a "total evidence" approach. Cladistics 26: 456-481.

Tedford, R. H., X. Wang & B. E. Taylor. 2009. Phylogenetic systematics of the North American fossil Caninae (Carnivora: Canidae). Bulletin of the American Museum of Natural History 325: 1-218.


  1. Ahh, gotta love fossil dogs!

    Can one tell if the coyote is member of the wolf group that never left North America or part of repeated colonizations of the continent?

    How far into the pleistocene did the north american 'jackals' survive to?

  2. It seems likely that the coyote is a colonist from Eurasia. Tedford et al.'s proposed phylogeny has been uploaded to Wikipedia; they derive the coyote from the Eurasian Canis edwardii, as the sister taxon to the golden jackal. Some authors proposed the North American C. lepophagus as the ancestor of the coyote but, as noted in the post, that seems to have been a more basal species. There were probably at least five colonisations of the New World: C. latrans, C. lupus, C. armbrusteri, Xenocyon and Cuon alpinus, though, considering the interfertility of dog species, this is probably oversimplifying matters a bit.

    The North American 'jackals' survived until quite recently (see the figure linked to above), certainly overlapping with the quite late dire wolf, though I don't know if they would have been around to see humans arrive in the Americas. Fossil remains of this group are apparently not very abundant.

  3. A few things I'd like to mention or ask in reaction to your great article:

    - What about *Megacyon* from Indonesia? I've read that these were probably descended from (or members of) the *Xenocyon* lineage too. Also, if *Cuon*,*Cynotherium*, *Lycaon* and *Megacyon* are part of the *Xenocyon* clade, shouldn't these genera either be merged into *Xenocyon* or the latter further separated into different genera? (Arguably, if its true that the 'other jackals' are indeed less closely related to wolf-group *Canis* than the *Xenocyon*-group is and we insists on classification in *Canis*, the whole bunch might have to be merged into *Canis*.
    Given that, as far as I can tell, *Xenocyon* has received little attention (it was even hardly given a mention in 'Dogs: Their fossil relatives and evolutionary history' by Wang & Tedford) , I doubt its internal phylogeny is understood too well, though. Paleomammalogists also seem more comfortable with paraphyletic genera than do, say, dinosaurologists.

    - Honourable mentions might also go to *Indocyon* and *Cubacyon* from Cuba. They may be insular canids or they may be early domestic dogs, in any case they seem to be allied to *Canis* and kin.

    - Is *C. simiensis* also a member of the wolf-clade or is it more basal, but still more derived than *C. aureus*?

    - Do you think that traditional *C. lupus* should be split into several different species, as has been proposed?

  4. The suggestion has indeed been made to merge what I've called the Xenocyon lineage into a single genus, which then would be Lycaon. So far, this doesn't seem to have garnered many adherents. As far as I know, no-one has suggested merging Lycaon and its relatives into Canis, though Cuon alone has sometimes been included in Canis.

    As mentioned in the post, the Simien jackal is a part of the wolf group. IIRC, Prevosti (2010) placed it basalmost in the group, but I forget what molecular analysis has suggested. Considering the high level of hybridisation in the group, it is possible that an analysis that assumes dichotomous branching may not even be appropriate: for instance, Prevosti's morphological analysis places the red wolf Canis rufus as the sister to C. aureus, when it is more likely derived (as shown by molecular analysis) from hybridisation between the coyote and a wolf (probably C. lycaon).

    As for recognising separate wolf species, the earlier post linked to at the top of this one comments to some degree on that. To a certain extent, the nature of the wolf group makes the question 'how many species' almost unanswerable, because gene flow between 'species' is, while very low, probably not negligible.

  5. "As far as I know, no-one has suggested merging Lycaon and its relatives into Canis, though Cuon alone has sometimes been included in Canis."

    Actually, I have seen *Lycaon* being merged with *Canis* in a paper discussing the African predator community at the time of early *Homo*. I can't seem to locate it now, though. That's a minor quibble though.
    Personally, I'd prefer recognising *Lupulella* and *Schaeffia* over bloating *Canis* to include *Xenocyon* and its descendants.

    Regarding hybridisation, do you know if *Canis* has ever succesfully hybridised with *Lycaon* or *Cuon*? Or even the latter two together? For that matter, are there any records of hybridisation between striped or black-backed jackals and members of the wolf-group on record?

  6. I'm not aware of any dhole or hunting dog hybrids, and a quick google search doesn't reveal anything. But it's worth noting that the main limiting factors on hybridisation between the dogs that are interfertile (eg. wolf/coyote) are behavioural, and the hypercarnivorous dogs are behaviourally even more distinct than those two are. There also don't appear to be any records of hybrids involving black-backed or side-striped jackals.

  7. "there is some uncertainty about whether the European C. cipio should be treated as Canis or assigned to the related, slightly earlier fossil genus Eucyon"

    According to Rook (2009), cipio should be placed in Eucyon.

    "Removal of the latter two species from Canis into separate genera as Schaeffia adusta and Lupulella mesomelas to preserve monophyly has been suggested, but almost universally ignored"

    Give it time. That those two 'jackals' should be removed from Canis is a change that I'm fairly confident will be widely accepted eventually (and probably quite soon, too).

    Oh, and great article!

    Rook, L. 2009. The wide ranging genus Eucyon Tedford & Qiu, 1996 (Mammalia, Carnivora, Canidae, Canini) in the Mio-Pliocene of the Old World. Geodiversitas 31: 723-741.

  8. There is a Thai spitz said to be a jackal hybrid.
    Spitz dogs (only) have mixture with Tamyr wolf.
    I consider domestication of dogs occurred at Phu Quoc Island & possible source of "Cuon".


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