Extinct Western Camel Fact Sheet, 2009

Extinct Western Camel, Camelops hesternus
February 2009

Fact Summary
Taxonomy and Nomenclature
Distribution and Habitat
Physical Characteristics
Behavior and Ecology
Diet and Feeding
Reproduction and Development
Diseases and Pathology
Web Resources
Bibliography

TAXONOMY & NOMENCLATURE *
*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.

(Cui et al 2007) (Dalquest 1992) (Honey et al 1998)(Janis et al 2002)(Kurtén & Anderson 1980) (McKenna and Bell 1997) (Webb 1977) (Whistler and Webb 2005)
Describer (Date): Leidy 1873

Kingdom: Animalia
    Phylum: Chordata
        Class: Mammalia
             Order: Artiodactyla (pigs, camels, deer, giraffes, cattle, and their kin)
                Superfamily: Cameloidea
                    Family: Camelidae
                          Subfamily: Camelinae
                              Tribe Lamini (extinct genera, guanacos,llamas, vicuñas)
                                    Genus: Camelops
                                          Species: Camelops hesternus - Extinct Western Camel or Yesterday's Camel
                              Tribe: Camelini (extinct genera plus dromedary and bactrian camels)

Taxonomic History and Nomenclature

Scientific Name: From the Latin word "hesternus" meaning "of yesterday" - Yesterday's Camel.
Common Name: Yesterday's Camel or the Extinct Western Camel
The camel family is divided into two main tribes; living species today include:
- Old World dromedary and bactrian camels
- New World guanaco, llamas, alpaca, and vicunas.
Camelops is more closely related to llamas than to modern camels (Webb et al 2006)
Six species of Camelops have been named, but the genus is in need of revision. (Kurtén & Anderson 1980) (Dalquest 1992)
A very large individual Camelops has been discovered that may be either C. hesternus or a new species. (Webb et al 2006)

Phylogeny

The camelid family began in North America some 45 million years ago in the Eocene Epoch. (Whistler and Webb 2005)
- Sheep-sized Poebrotherium is the most primitive camel-like ancestor. (Janis et al 2002)
A drying trend that produced the first areas of true savanna in North America coincided with the rise of camels. (Webb 1977)
A small camel, Miotylopus, lived in southern California, around 28 million years ago.
New DNA studies imply that the two camel family tribes diverged some 25 million years ago, much earlier than previously believed. (Cui et al 2007)
Between 20 and 14 million years ago, some 13 genera of camels flourished throughout North America. (Honey et al 1998)
By 7 million years ago, camels had spread to other continents, as did the horses. (Whistler and Webb 2005)
During the Pleistocene, at least five genera of camels lived in North America. (Dalquest 1992)
At end of the Pleistocene, both camels and horses in North America were extinct.(Kurtén & Anderson 1980)

DISTRIBUTION & HABITAT *
*How Do We Know This? Scientists use knowledge of the earth's rocks, global plate tectonic movements,
and the chemical process of fossilization to make sense of fossil distribution patterns and ancient habitats.

(Shaw 2001) (Webb et al 2006)
Prehistoric Distribution:

Central and western North America, including Rancho La Brea. (Webb et al 2006).
Camelops hesternus fossils at La Brea asphalt deposits include some 2700 bones from 36 individuals. (Shaw 2001)

Habitat:

Like modern camels, Camelops was adapted to open spaces and dry land.
It is not known if Pleistocene camels had modern camels' superb ability to conserve water (Webb et al 2006)
- Adaptations to arid conditions may have evolved after migration out of North America.

PHYSICAL CHARACTERISTICS*
*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, skin and hair impressions or actual skin or hair is preserved.
Body weight is more difficult to gauge because fat leaves no impression on the skeleton.

(Dalquest 1992) (Janis et al 2002) (Webb 1965)
Estimated Body Weight: Perhaps up to 800 kg (1764 lbs)
( 20 % larger than than modern camels that weigh 650 kg (1,433 lbs)
Estimated Height at Shoulder: 2.2 m (7 ft)
Tail Length: A short tail

General Description

A medium to large-sized camel with foot structure like that of modern camels (Janis et al 2002)
Not known with certainty whether Camelops had a hump.(Webb 1965)
Fossils in the genus Camelops are best distinguished by stocky foot bones with a unique ligament scar on the last toe bones.

Teeth

High crowned (hypsodont) teeth adapted for an abrasive diet
No third premolars in the lower jaw (Webb 1965)
Although molar teeth have been used to identify many species of Camelops, these teeth have limited diagnostic value. (Dalquest 1992)

Pelage

Unknown but most likely similar to modern dromedary and bactrian camels

Sexual Dimorphism

Differences seen in size of lower jaws, length and robustness of limb bones.

Other Physical Characteristics

As in all camelids, long toe and finger bones (medapodials) allow for a long stride and a pacing gait (Webb et al 2006)
Hand and foot bones are good indicators of size for Camelops species.
Limbs are long.
The two toes of Camelops are splayed wide to give support and stability (Webb 2006)

BEHAVIOR & ECOLOGY*
*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.

(Gauthier-Pilters & Dagg) (Lockley and Hunt 1995) (Morgan & Rinehartl 2007) (Webb 1972)

Social Life

Not known but may have been similar to modern camels that form small family groups of 2-20 individuals.

Locomotion

Highly adapted for running
A pacing gait (feet move together on one side at a time) evolved early in camel evolution (Webb. 1972)
Pacing gait appears to have evolved before the spread of grasslands in the Miocene Epoch. (Janis et al 2002)
- Pacing allowed a long stride and less expenditure of energy for covering wide distances (Webb 1972) (Lockley & Hunt 1995)
- This gait may be preserved in 15 million-year-old Miocene trackways of extinct camelids from the Mojave Desert (Webb 1972)
Fossil camelids in the American Southwest have been called the first prairie schooners for their supposed ability to travel efficiently across the desert. (Lockley and Hunt 1995)

Interspecies Interaction

Shared grassland and conifer forest margins with small mammals such as the Northern Pocket Gopher (Thomomys talpoides), a species only found at higher elevations today or in more northern locales (Morgan & Rinehart 2007)
Very often found at sites that have bison and horse fossils.

DIET & FEEDING*
*How Do We Know This? Clues to fossil mammals' diets come from teeth,skull shape,
from fossil dung and gut contents, from lab analysis of oxygen isotopes in bone and teeth,
and by looking at diets of similar modern animals.
(Dompierre & Churcher 1996) (Vetter et al 2008)

A herbivore adapted for browsing or mixed browsing. (Dompierre & Churcher 1996)
Carbon isotope studies of teeth show Camelops ate both C-3 plants and C-4 drought tolerant grasses.
- A high proportion of C-4 vegetation such as saltbush (Atriplex) in Camelops diet in Nevada's Pleistocene (Vetter et al 2008)

REPRODUCTION & DEVELOPMENT *
*How do We Know This? Isotope studies of elements present fossil bones and tusks
in microscopic quantities give information about timing of reproductive stress, and timing of nursing.
Clues to stages of development come from tooth replacement patterns and closure of sutures
in skull and limb bones.

(Morgan & Rinehart 2007)

Life Stages

Juvenile Camelops are recognized by the same criteria that identify modern young camels (baby teeth, unfused ends of long bones and unfused vertebrae)
Old age individuals are identified by large size, worn teeth, and age-related arthritic bones.

Mortality

Large cats such as Smilodon and the American Lion (Panthera atrox) and Dire Wolves (Canis dirus) might have preyed on these camels.

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

(Morgan et al 2005) (Rothschild 2003)

Osteoarthritis was absent in Camelops bones from Natural Trap Cave in Wyoming (Rothschild 2003)
Osteoarthritis was present in toe bones of an old age Camelops trapped in a Late Pleistocene fissure deposit in New Mexico. (Morgan et al 2005)

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

FAUNMAP -- This useful website created and maintained by the Illinois State Museum gives the known distributions in map and list format for many fossil species in North America.
The Paleobiology Database -- This site is a scientific organization run by paleontological researchers from around the world. It features taxonomic and distribution information for the entire fossil record.

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