Dire Wolf, Canis dirus
July 2009

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Dire wolf (Canis dirus) from Rancho La Brea, Calif.; detail of a mural. From Wikimedia Commons. Public domain.

*How Do We Know This? Like living animals, fossil remains of once-living animals are
classified and grouped according to their relationships to each other and to their ancestors.

(ITIS 2010) (Anyonge & Roman 2006) (Lindblad-Toh et al 2005) (McKenna & Bell 1997) (Tedford et al 2009) (Wilson & Reeder 2005) (Wang et al 2004)

Describer (Date): Leidy 1858 for Canis dirus. Linnaeus 1758 for genus Canis

Kingdom: Animalia
    Phylum: Chordata
        Class: Mammalia
             Order: Carnivora
                   Suborder: Caniformia (dog-like carnivores; includes many extinct families)
                          Family: Canidae (dogs, coyotes, foxes, jackals, wolves; many extinct genera)
                               Genus: Canis (6 living species)
                                  Species: Canis dirus EXTINCT
                                      Subspecies: Canis dirus guildayi   EXTINCT
                                      Subspecies: Canis dirus dirus    EXTINCT                  
                   Suborder: Feliformia (cat-like carnivores; many extinct families)

Taxonomic History and Nomenclature

Phylogeny (Wang et al 2004) (Tedford et al 2009) (Lindblad-Toh et al 2005)

*How Do We Know This? Scientists make sense of fossil
distribution patterns using knowledge of the earth's rocks, global plate
tectonic movements, plus genetic and phylogenetic studies.
Ancient habitats are revealed by studies of modern environments where sediments
are deposited, taking into account the chemical processes of fossilization.

(Anyonge & Baker 2006) (Coltrain et al 2004) (Dundas 1999) (Hodnett et al 2009) (Hunt 1996) (Prevosti & Rincon 2007) (Stock & Harris 1992)

Prehistoric Distribution Habitat

*How Do We Know This? Careful study of fossil bone or tooth anatomy yields
much exact information about placement and strength of muscles, tendons,
ligaments, nerves, and blood vessels. In rare cases, scales, skin, nails or hairs leave impressions
in sediments. Even more rarely, actual skin, nails, or hair is preserved. Body weight is more difficult
to gauge because fat leaves no impression on the skeleton.

(Turner & Anton 1997) (Anyonge et al 2003) (Anyonge & Baker 2006) (Anyonge & Roman 2006)

Estimated Body Weight: 34-67kg (75-148 lb) (Anyonge & Roman 2006)
Head/Body Length: 125 cm (4.1 ft) (Anton & Turner 1997)
Height at Shoulder: 80 cm (2.6 ft)
Tail Length: 63 cm (2 ft)

General Description
Teeth Pelage Sexual Dimorphism Other Physical Characteristics

*How Do We Know This? Since direct observation of a fossil animal's behavior
isn't possible, paleontologists use comparison and contrast with living animals for
guidance. Tracks can sometimes reveal further clues. Associated animals and
plants found at a fossil site can suggest predator/prey dynamics and dietary options.

(Binder et al 2002) (Hodnett et al 2009) (Van Valkenburgh et al 1990) (Van Valkenburgh & Hertel 1993) (Van Valkenburgh & Sacco 2002)

Social Life (Van Valkenburgh & Sacco 2002)
Interspecies Interaction

*How Do We Know This? Clues to fossil mammals' diets come from not only teeth,
but also skull shape, from fossil dung and gut contents, from microscopic viewing of
wear on teeth, from lab analysis of oxygen, carbon, and nitrogen isotopes in bone and teeth, and by looking
at diets of similar modern animals.

(Anyonge & Roman 2006) (Coltrain et al 2004) (Ewer 1973) (Fox-Dobbs et al 2003) (Fox-Dobbs et al 2007) (Harris et al 2004) (Hodnett et al 2009) (Therrien 2005) (Van Valkenburgh & Ruff 1987) (Van Valkenburgh 1998) (Van Valkenburgh & Sacco 2002)

*How do We Know This? Abnormalities in fossils bones may show evidence
of arthritis, cancer, nutritional stress, fractures and more.

(Duckler & Van Valkenburgh 1998) (Binder et al 2002)

Important Web Resources (and where to view fossils in museums):