Mammalia, Carnivora, Canidae, Caninae
CANIS DIRUS LEIDY, 1858
Common Name: dire wolf
Alternate Scientific Name: Canis primaevus (of Leidy, not Hodgson), Canis indianensis, Canis mississippiensis, Canis ayersi, Aenocyon ayersi, Aenocyon dirus
Source of Species Name: from the Latin word dirus, meaning fearful or ominous.
Age Range: late middle to late Pleistocene; late Irvingtonian and Rancholabrean land mammal ages, from about 500,000 to 11,000 years ago.
Florida Fossil Occurrences:
Figure 1. Map of Florida, with black circles indicating counties where fossils of Canis dirus have been found (the circles do not indicate a specific location within the county where the fossils were found, and some counties may have two or more different locations producing this species).
Florida Fossil Sites with Canis dirus:
Alachua County—Arredondo 1A; Arredondo 2A; Haile 8A; Haile 19C; Haile 19D; Haile 20A; Haile 20B; Hornsby Springs
Charlotte County—Flamingo Waterway; Port Charlotte Area
Citrus County—Lecanto 2A
Columbia County—Ichetucknee River; Santa Fe River 1; Santa Fe River 2; Santa Fe River 3; Santa Fe River 4A; Santa Fe River 10; Wilson Springs
Dade County—Cutler Hammock Site; Monkey Jungle 1
De Soto County—Peace River 3A
Dixie County—Steinhatchee River 3
Duval County—Jacksonville Beach
Hardee County—Peace River 11; Peace River 13
Hillsborough County—Cow House Slough 2
Indian River County—Vero Canal Site
Jackson County—Chipola River 2; Peccary Tooth Cave
Jefferson County—Aucilla River 1B
Levy County—Devil’s Den; Waccasassa River; Wekiva River
Manatee County—Bradenton 51st Street
Marion County—Eichleberger Cave; Johnson Creek; Oklawaha River 1; Oklawaha River 2; Rainbow River; Reddick 1A; Reddick 1B; Reddick 1C; Silver Glen Springs; Withlacoochee River
Nassau County—North Fernandina Beach
Okeechobee County—Kissimmee 6
Orange County—Rock Springs
Pinellas County—Millennium Park; Seminole Field
Putnam County—St. Johns Lock
Sarasota County—Big Slough; North Havana Road
Seminole County—Wekiwa River 2
St. Lucie County—Dickerson Coquina Pit
Taylor County—Aucilla River 1A; Aucilla River 3E; Aucilla River 3J
Overall Geographic Range: Earliest records are from the middle Pleistocene (late Irvingtonian) of Nebraska and California (Tedford et al., 2009). Extensively distributed in North America in the late-middle and late Pleistocene (Rancholabrean), ranging north-south from southern Canada to southern Mexico, and east-west from the Atlantic coast to the Pacific. Also known from Venezuela, Ecuador, Bolivia, and Peru in South America (Dundas, 1999; Tedford et al., 2009). The type locality is from the Ohio River, near Evansville, Vanderburgh County, Indiana (Nowak, 1979); its age is assumed to be late Pleistocene.
Comments: Canis dirus, the dire wolf, is the largest species in the genus Canis, with an estimated mass of 130 to 150 pounds (60-70 kg) (Anyonge and Roman, 2006;
Wang et al., 2008). This is about 25% heavier than the modern gray wolf, Canis lupus. Overall, compared to most other extinct and extant members of Canis, the dire wolf had a larger
body size, a wider and taller skull with a great sagittal crest and extension in the back (posterior) of the skull, a thickening of the mandible below the carnassial teeth (upper fourth premolar and
lower first molar), and the carnassials were slightly larger and more massive (Kurtén, 1984; Anyonge and Baker, 2006). These features gave the dire wolf larger and more powerful jaw muscles,
which enabled it to be quite efficient at capturing and killing prey. Also, dire wolves had shorter limbs relative to body mass and would have been stockier than most other wolves. While
this means that they were poorer runners compared to modern wolves or coyotes, they would still have been active pursuit predators, and not limited to ambush-style attacks. Like most dogs and wolfs,
Canis dirus undoubtedly chewed and gnawed on bones. But it lacks the specialized bone-crushing adaptations found in the skulls and teeth of hyenas and Borophagus (Anyonge and Baker, 2006).
Figure 2. UF/FGS 280, partial skull of Canis dirus with right I1, I3, P1-P4, M1 and left P1, P4, M1 and braincase, from Vero Canal Site Indian River County, Florida. This is the holotype specimen of Canis ayersi Sellards, 1916, now considered a junior synonym of Canis dirus, collected in 1916 . A, dorsal view; B, lateral view; C, ventral view.
Figure 3. UF 3988, right partial maxilla of Canis dirus with P2-M2 from Hornsby Springs, Alachua County, Florida; late Pleistocene. A, lateral view; B, ventral (occlusal) view; C, medial view.
In 1854, a partial left maxilla of a large wolf was discovered in the bed of the Ohio River near Evansville, Indiana in
association with other extinct Pleistocene species such as Megalonyx jeffersoni and Equus complicatus. The state geologist of Indiana, Joseph G. Norwood, sent the specimen to Joseph
Leidy (1823-1891), the preeminent vertebrate paleontologist in North America at the time. Leidy recognized it as a new species and originally named it Canis primaevus. However, that species
name was previously used for a species of dhole, a modern canid from Southeast Asia (Cohen, 1978). So in 1858 Leidy gave the fossil from Indiana the much more appropriate replacement name Canis
dirus. As additional fossils of large Pleistocene wolves were found in North America in the late 1800s and early 1900s, some were given “regional” names, such as Canis
indianensis and Canis mississippiensis. These are now regarded as junior synonyms of Canis dirus (Kurtén, 1984).
The last named species of dire wolf in North America came from Florida. A relatively complete skull of a large wolf was found by Frank Ayers in Stratum 2 of the Vero Canal Site in May 1916 (Figure 2). Florida State Geologist E. H. Sellards was already preparing a description of the fossils from this site for publication of that year’s annual report of the Florida Geological Survey. Sellards quickly made comparisons of this skull and some other, less complete fossils from Vero, with the type specimen of Canis dirus and a specimen from the recently discovered Rancho la Brea site in California. Sellards (1916) described the Vero skull as being very similar to and belonging to the same group as Canis dirus, but having a distinctly narrower snout. While Sellards (1916) formally named the Vero wolf Canis ayersi to honor its discoverer, he astutely noted (p. 156) that the differences he observed between the specimens he had on hand might turn out to be the result of individual and geographic variation. Later discoveries have borne this out, and Sellards’ species is universally considered a junior synonym of Canis dirus (Nowak, 1979; Kurtén, 1984).
Figure 4. UF 2259, right partial mandible with p3-m3 of Canis dirus from Bradenton 51st Street site, Manatee County, Florida; late Pleistocene. A, occlusal view; B, medial view.
Figure 5. Lateral views of two mandibles of Canis dirus from the late Pleistocene of Florida. A, UF 2259, right partial mandible with p3-m3 of Canis dirus from Bradenton 51st Street site, Manatee County. B, UF/TRO 16, left mandible with p3, m1-m2 from Devils Den, Levy County. The specimen in A has been digitally flipped so it appears to be from the left side, allowing better comparison between the two specimens. UF/TRO 16 is a subadult individual with unworn teeth, while UF 2259 is a older adult with well worn teeth. Note the deepened ramus and added muscle scars that form as the animal matures.
Kurtén (1984) recognized two subspecies of Canis dirus after studying limb proportions of dire wolf specimens east and west
of the Rocky Mountains. Specimens west of the Rockies, ranging mostly in California and Mexico, were given the name Canis dirus guildayi and had shorter limbs, especially distally, than dire
wolves east of the Rockies. Dire wolves living east of the Rockies, which would include Florida, were placed in the subspecies Canis dirus dirus. They had longer limbs and were on average
larger in terms of body size than the western form (Kurtén, 1984).
The evolutionary origin of Canis dirus has been a point of contention, with some authors even favoring a South American ancestry followed by a back dispersal to North America. The proposed South American ancestor, Canis nehringi, is pheneticly similar to Canis dirus (Nowak, 1979; Dundas, 1999). The recent review of Tedford et al. (2009) favors a simpler answer, with derivation from a smaller species of wolf from the early to middle Pleistocene of North America, Canis armbrusteri. The latter itself dispersed from Asia in the early Pleistocene.
The largest known sample of Canis dirus specimens is from the Rancho La Brea tar pits in Los Angeles, California, with over 1,600 known individuals. These tar pits are famous for trapping and preserving an abundance of fossils, especially carnivores and scavengers. Likewise, the Talara tar pits of Peru produced the largest sample of the species in South America. Unfortunately, no such deposits are known from Florida. The locality in Florida providing the greatest numbers of dire wolves is the Cutler Hammock Site in Dade County. It contained fossils representing a minimum of 42 individuals ranging from young pups to old adults and is thought to have been a dire wolf den (Emslie and Morgan, 1995). Another important area in Florida for Canis dirus is the Aucilla River in Jefferson and Taylor counties. According to Gillette (1979), the largest known dire wolves specimens have been recovered from this region.
Canis dirus displays only minor sexual dimorphism and most likely lived in social groups, in packs, much like modern gray wolves. This would also indicate monogamy, which is common among members of the Canidae (Wang et al., 2008). Studies on large predators in modern Africa reveals intense, sometimes deadly competition for carcasses and territory between large carnivores. Hunting in packs would have allowed dire wolves to successfully kill larger prey than could a single individual. Pack behavior would also be important to protect carcasses from larger predators of the late Pleistocene, such as bears (Arctodus, Tremarctos) and the great cats (Smildon fatalis, Panthera atrox), and allowed them to take prey carcasses away from more solitary predators such as jaguars. The Cutler Site may give some insight into the preferred diet of Canis dirus, as it contains numerous bones, often fragmented, and isolated teeth of peccaries and horse. The latter were mostly young juveniles. It is possible that larger prey were consumed at the kill site, so only these relatively smaller items were brought back to the den.
In addition to large bears and great cats, Canis dirus also faced competition from other large, predacious members of the canid family. Three canid lineages dispersed from Asia into North America during the middle to late Pleistocene. The genus Xenocyon is widely distributed in the Pleistocene of the Old World and a close relative of the modern African hunting dog Lycaon pictus and the dhole Cuon alpinus (Martinez-Navarro and Rook, 2003; Tedford et al., 2009). Its fossils are very rare in North America, and it is not known south of the Texas panhandle. The dhole also dispersed into North America, but its fossils are only known from one locality in New Mexico (Tedford et al., 2009). The third disperser from Asia is the gray wolf, Canis lupus. According to Tedford et al. (2009), it first appears in Alaska and the Yukon in the middle Pleistocene, but does not disperse into lower latitudes until the late Pleistocene. Tedford et al. (2009) referred all middle Pleistocene records of Canis lupus from Nebraska to other species of Canis. Most fossil records of Canis lupus are from western North America, overlapping its historic range, and it is not known from Florida. Whether because of direct competition with Canis dirus or other reasons, neither Xenocyon nor Cuon persisted long in North America, nor were they ever common. Likewise, the gray wolf did not become common until after the extinction of Canis dirus at the end of the Pleistocene.
The main sources of prey for dire wolves were Pleistocene megafauna (peccaries, horse, llama, bison, tapir, sloths, glyptodonts, etc.). At the end of the Pleistocene, most these species became extinct. At this time, about 11,000 years ago, Canis dirus and Canis lupus were co-existing in the west, while Canis dirus and the red wolf Canis rufus lived together in the east (Dundas, 1999; Nowak, 2002). Canis dirus had previously been the more abundant large canid across the continent. But it was its smaller, quicker relatives that survived the terminal Pleistocene extinction event.
Figure 6. UF 8211, metatarsal 4 of Canis dirus in anterior, medial, and posterior views (left to right), from the Ichetucknee River, Columbia County, Florida; late Pleistocene. Such a long, slender distal leg bone is characteristic of dire wolves from eastern and central North America.
Scientific Publications and Other References Cited:
Anyonge, W., and A. Baker. 2006. Craniofacial morphology and feeding behavior in Canis dirus, the extinct Pleistocene dire wolf. Journal of Zoology 269(3):309-316. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2006.00043.x/full
Anyonge, W., and C. Roman. 2006. New body mass estimates for Canis dirus, the extinct Pleistocene dire wolf. Journal of Vertebrate Paleontology 26(1):209-212. http://www.jstor.org/stable/4524553
Cohen, J. A. 1978. Cuon alpinus. Mammalian Species 100:1-3. http://www.science.smith.edu/msi/pdf/i0076-3519-100-01-0001.pdf
Dundas, R. G. 1999. Quaternary records of the dire wolf, Canis dirus, in North and South America. Boreas, Vol. 28(3):375-385. http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3885.1999.tb00227.x/pdf
Emslie, S. D., and G. S. Morgan. 1995: Taphonomy of a Late Pleistocene carnivore den, Dade County, Florida. Pp. 65-83 in D. W. Steadman and J. I. Mead, J. I. (eds.), Late Quaternary Environments and Deep History: A Tribute to Paul S. Martin. The Mammoth Site of Hot Springs, South Dakota, Scientific Papers 3.
Kurtén, B. 1984. Geographic differentiation in the Rancholabrean dire wolf (Canis dirus Leidy) in North America. Pp. 218-227 in H. H. Genoways and M. R. Dawson (eds.), Contributions in Quaternary Vertebrate Paleontology: A Volume in Memorial to John E. Guilday. Carnegie Museum of Natural History, Pittsburgh.
Martínez-Navarro, B., and L. Rook. 2003. Gradual evolution in the African hunting dog lineage: systematic implications. Comptes Rendus Palevol 2(8):695-702. http://dx.doi.org/10.1016/j.crpv.2003.06.002
Nowak, R. M. 1979. North American Quaternary Canis. Monograph of the Museum of Natural History, University of Kansas 6:1-154.
Nowak, R. M. 2002. The original status of wolves in eastern North America. Southeastern Naturalist 1(2):95-130. http://www.bioone.org/doi/full/10.1656/1528-7092%282002%29001%5B0095%3ATOSOWI%5D2.0.CO%3B2
Sellards, E. H. 1916. Human remains and associated fossils from the Pleistocene of Florida. Florida Geological Survey, Annual Report 8:121-160. http://fulltext.fcla.edu/DLData/CF/CF00001581/file4.pdf
Tedford, R. H., X. Wang, and 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. http://hdl.handle.net/2246/5999
Wang, X., R. H. Tedford, and M. Anton. 2008. Dogs: Their Fossil Relatives and Evolutionary History. Columbia University Press, New York.
Original Author(s): Rachel E. Narducci
Original Completion Date: October 5, 2012
Editor(s) Name(s): Richard C. Hulbert Jr.
Last Up-dated On: October 16, 2013
This material is based upon work supported by the National Science Foundation under Grant Number CSBR 1203222, Jonathan Bloch, Principal Investigator. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
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