Columbian Mammoth & Channel Island Mammoth
*How Do We Know This? Like living animals, fossil remains of once-living animals
classified and grouped according to their relationships
each other and to their ancestors.
Many Pleistocene fossils yield DNA which helps scientists determine these animals'
similarity to living animals.
(Agenbroad 2003) (Agenbroad and Mead 1996)(Cohen 2002) (Harrington 1984) (Krause et al 2006)
(Lister 1996) (Lister 2007) (Lister and Sher 2001) (McDaniel 2006) (McDaniel and.Jefferson 2003) (Miller et al 2008)(Osborne 1942)
(Roth 1984, 1996) (Shaw & Quinn 1986) (Shoshani 1998, 2005) (Todd & Roth 1996)
Describer (Date): Brookes 1828 for Mammuthus
Falconer 1857 for Mammuthus columbi
Stock and Furlong 1928 for Mammuthus exilis
Order: Proboscidea (mammoths, mastodonts, shovel-tuskers, modern elephants)
Family: Elephantidae (Asian and African elephants, mammoths)
Species: Mammuthus meridionalis (Southern Mammoth)
Species: Mammuthus trogontherii (Steppe Mammoth)
Species: Mammuthus primigenius (Woolly Mammoth)
Species: Mammuthus columbi (Columbian Mammoth)
Species: Mammuthus exilis (Channel Island Mammoth)
Taxonomic History and Nomenclature
- Common Names: The word mammoth comes from Russian "mamot", "mamont" and possibly the Tartar word "mamma" meaning "earth".
- The word for mammoth may reflect a folk belief that the animal whose bones were always found in the ground actually lived in burrows underground (Cohen 2002)
- The Columbian or American Mammoth was named in honor of Christopher Columbus
- The Channel Island Mammoth is named for islands off coastal southern California where it lived
- Scientific Names:
- Mammuthus columbi - see above
- Mammuthus exilis - exilis is the Latin word for 'small' or 'slender'
- Three main lineages of mammoths all originated in Europe and Asa
- Researchers recognized varying number of mammoth species from North America
- Sixteen species in three genera. (Osborne 1942)
- Four species (Todd & Roth 1996)
- Seven species (Madden (1981)
- Some researchers consider the dwarf mammoth a subspecies of M. columbi, others consider it a separate species. (discussion in Roth 1984)
- Earliest elephant-like animals lived 58 million years ago (Shoshani 1998)
- Mammoths and Asian elephants diverged from African elephants about 4 million years ago. (Lister and Sher 2001)
- The entire genome for one mammoth species (the Woolly Mammoth) has now been sequenced
- Mammoths are closer to Asian than to African elephants (Krause et al 2006)
- Mammoths first lived in Europe and Asia some 2.5 million years ago. (Lister 1996)
- Early populations of Steppe Mammoths evolved into Columbian mammoths in North America and Wooly Mammoths in Eurasia. (Lister 2007)
- Mammoths entered the North America about 1.7 to 1.2 million years ago. (Harrington 1984)
- Mammuthus columbi lived in North America by 1.1 million years ago (McDaniel and Jefferson 2003)
- Opinions differ on the most recent ancestor of the Columbian Mammoth:
- Considered to be the Imperial Mammoth (M. imperator) (Shaw and Quinn 1986) (Agenbroad & Mead 1996)
- But the Imperial Mammoth may instead be simply an early, large Columbian Mammoth (McDaniel & Jefferson 2005) (Marcus & Berger 1984)
- Considered to be the Southern Mammoth (M. meridionalis) (Agenbroad and Mead 1996)
- Or recently, considered to be the Steppe Mammoth (M. trogontherii) (McDaniel and Jefferson 2003)
- Since both Columbian and Southern mammoths occur together at Anza-Borrego State Park in California, the Steppe mammoth is more likely to be the Columbian's ancestor (McDaniel 2006).
- M. exilis existed on the Channel Islands at least 47,000 years ago; they evolved from Columbian mammoths (Agenbroad 1996)
- About 13,000 years ago they became extinct (Agenbroad et al 2003)
- M. columbi became extinct about 13,000 years ago
- Scientists have recently sequenced the nuclear genome of a related mammoth species, the Woolly Mammoth, using hairs from a mammoth mummy from Siberia (Miller and Schuster 2008)
PREHISTORIC DISTRIBUTION & HABITAT *
(Agenbroad 1998) (Agenbroad & Mead 1996) (Dudley 1996) (Johnson 1972) (Koch et al 1995) (Todd & Roth 1996)
*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.
- Columbian mammoths occupied North America from Canada to central Mexico. (Todd & Roth 1996).
- No mammoths dispersed into South America. (Dudley 1996)
- Columbian mammoths arrived on the Channel Islands at least by 47,000 years ago and eventually evolved pygmy individuals (Agenbroad 1996)
- Pygmy Channel Island Mammoths occupied what are now island remnants of a larger Pleistocene island. (Agenbroad 1998) (Agenbroad & Mead 1996)
- Sea levels rose when the last ice age ended, further isolating the island mammoths
and shrinking their habitat
- San Miguel and Santa Rosa islands all have pygmy mammoth fossils
- Extremely variable habitats
(Agenbroad & Mead 1996).
- From sea level to high elevation mountains of Colorado Plateau.
- From riparian, dune, grassland, to steppe-tundra
- Revealed by pollen and plant fragments in sediments and dung
- Habitat use for modern elephants can also be determined by study of isotopes of carbon, nitrogen, lead, and strontium
- These isotopes are deposited in bone tissue of modern and extinct elephants
- Each habitat has distinct isotope signature from plant types, soils, water. (Koch et al 1995)
- Mammoths, like elephants, modified their habitats
- Landscape of Channel Islands probably became more open grassland due to mammoth's activities (Johnson 1972)
- Forage in Channel Island habitats would have been a limiting resource, favoring smaller body size (Roth 1984)
*How Do We Know This? Careful study of fossil bone or tooth anatomy yields much
about placement and strength of muscles, tendons, ligaments, nerves,
and blood vessels.
In rare cases, skin and hair impressions or actual skin or hair remains.
Body weight is more difficult to gauge because fat leaves no impression on the skeleton.
(Averianov 1996) (Dudley 1999) (Gillette & Madsen 1993) (Haynes 1991) (Krause et al 2006)
(Laws 1966) (Lister 1996) (Maglio 1973) (Roth 1984, 1996) (Tassy & Shoshani 1996) (Fox et al 2003)
Estimated Body Weight: (Dudley 1999)
M. columbi : 5,000-10,000 kg (5.5 -11 tons)
M. exilis: 200-500 kg (0.2 - 0.6 tons)
Body Length: (Tassy and Shoshani 1996)
M. columbi : 4- 4.5 m (13-14.7 ft)
M. exilis: 160-200 cm (5.2-6.6 ft)
Tail Length: (Gillette & Madsen 1993)
M. columbi: 1000 mm (39.8 in), intermediate between tails of wooly mammoths & modern elephants
Shoulder Height: (Roth 1996)
M. columbi: 3.7- 4.3 m (12-14 ft)
M. exilis :120-180 cm (3.9-5.9ft)
- Mammoths are medium to large-sized elephants (Maglio 1973)
- The Columbian Mammoth is possibly the largest mammoth
- The Channel Island Dwarf mammoth is the smallest mammoth; less than 50 percent the size of a Columbian.
- One mammoth species, the Woolly Mammoth, has had its genome successfully sequenced (Krause et al 2006)
- Mammoths seen from the side are highest at the shoulders, sloping rearward with a slightly humped profile
- Asian elephants do not have such a sharp slope rearward from the shoulders
- African elephants have a dished (slightly slumped down) profile
- All mammoths are identified primarily by features of their teeth
- Thickness of enamel
- Number of enamel loops in the molar teeth, seen from bite surface view
- Columbian Mammoth molars have 5 to 8 enamel plates per 100 mm (3.9 in) (Maglio 1973)
- Channel Island Mammoth molars are like the Columbian's, only smaller
- Twenty six teeth in all
- Six sets of teeth in a lifetime
- Resemble Asian elephant teeth, with closed enamel loops viewed on chewing surface
- All mammoths have strongly curved and twisted tusks (Lister 1996)
- Tusks continue to grow throughout the mammoth's lifetime
- Life history data is stored in the dentin's growth bands (season of death, age at sexual maturation, calving, migration) (Fox et al 2003)
- Not known, but assumed like modern elephants, perhaps somewhat more hairy in colder climates
- Unlike the wooly mammoth whose hair visible in many well-preserved frozen individuals
Other Physical Characteristics
- Like all elephants, seen in several parts of the mammoth skeleton
- Differences between males and females in pelvic, skull, and limb bones (Averianov 1996) (Haynes 1991)
- Tusks of males longer and heavier than those of females (Shoshani 1996)
- Mammoth's ears, known from individuals frozen in permafrost, smaller than those of African elephants
- Tip of trunk ends with one finger-like process on top and a flap below (Shoshani 1996)
- Somewhat like Asian elephants' and unlike African elephant trunk with "fingers" above and below
- Musth gland on side of face
- Unique for elephants, found in all living elephants and known from woolly mammoths preserved in permafrost
- Assumed to have been present in elephant lineage for millions of years (Shoshani 1998)
- Suggests social system for many extinct elephants similar to modern elephants
- An unusually large brain compared to body size
(Tassy & Shoshani 1996)
- Similar to most primates
- Skull is lightened with air sacs in the bone
- Modifications in hyoid bones, tongue, and voice box allowed low frequency (infrasonic) communication
- Appear in elephant lineage by at least 24 million years ago.
- Channel Island Mammoths
- Extreme genetic dwarfing (Dudley 1999)
- Shortened lower limb bones relative to body size when compared to full size mammoths
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.
(Bongino 2007) (Fox et al 1992)
(Hoppe 2004) (Johnson 1978) (Martin 2005)
(Riney 2002) (Schmidt 1992) (Shoshani 1998)
- Assumed to be broadly similar to living elephants since mammoths, like living elephants, have a musth gland
- Used for establishing dominance hierarchy in males (Schmidt 1992)
- At a fossil site in Waco, Texas where many individuals became trapped in a hypothesized flash flood, evidence of herding behavior noted
(Fox et al 1992)
- Adults assumed defensive position around young
- Two juveniles died, held in the tusks of the adults (as if they were being lifted to safety above the water)
- At the Mammoth Site in South Dakota, most trapped individuals are young males
- Suggests herding behavior like elephants today where young males lack group protection
- Herd structure suggested for individuals that have similar carbon isotope values in their bones
and are buried in same localities
- Assumption made that members of herd traveled ate same foods, drank same waters, ingested same minerals (Hoppe 2004)
- Not all individuals buried together represent a herd (Hoppe 2004)
- Bones may be from animals that have accumulated over time, not from ones that lived together
- Individuals buried at different times will have different carbon isotopes
- No predators preyed on mammoth adults, but young would have been vulnerable to attack by saber toothed cats (Smilodon and Homotherium), the American Lion (Panthera atrox), and the Short-Faced Bear (Arctodus).
- Like the modern elephants, Columbian Mammoths would have been a keystone species
with a profound effect on its ecosystem
- Mammoths enhanced habitats for other species by maintaining trails, keeping water ways accessible, maintaining open grassy areas.
- A fossil discovery near Oceanside, California had multiple mammoth sized tracks, plus mammoth and many other species' bones (fox, coyote, tapir, bison, pond turtle, mastodon) on the margins of an oxbow lake (Riney 2006)
- Hunted by humans
- Some 20 known North American sites associated with Clovis people's stone points (Martin 2005)
- Mammoth's feeding habits may explain many anti-herbivory compounds in modern native plant communities (Dudley 1999)
- Columbian mammoths were good swimmers; they crossed open water to reach the Pleistocene Channel Island.
- Even at lowest sea levels, no land connection existed with the mainland. They had to swim to reach the islands. (Johnson 1978)
DIET & FEEDING*
*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 lab analysis of isotopes
of elements in bone and teeth, and by looking at diets of modern animals.
(Agenbroad & Mead 1996) (Coltrain et al 2004) (Dudley 1999)(Fox et al 1992) (Hoppe 2004) (Koch et al 1988)
- Opportunistic feeders like elephants, mammoths varied their food intake regionally and seasonally. In general, a mixed grazing and browsing diet (Koch et al 1988)
- Mammoth dung deposits in two caves on Colorado Plateau contain pollen and plant fragments from mammoths' food (Agenbroad & Mead 1996).
- Water sedges, pondweed, elderberry, snowberry, wild rose, raspberries, currants, spruce, sagebrush, water birch, oak, juniper, grasses, and prickly pear cactus
- Carbon isotopes in skeleton of 20,000 year-old mammoths also give dietary clues
to the types of plants consumed
- At Rancho La Brea asphalt pits in southern California, no evidence of eating C-4 plants (warm-temperature grasses and other drought-resistant vegetation) (Coltrain et al 2004).
- At a mammoth site in Waco, Texas, C-4 plants were a main component of the diet (Hoppe 2004)
- In Florida mammoths ate mostly C-4 plants between 23,000 and 13,000 years ago (Koch et al 1998)
- Mammoth's feeding habits may explain modern native plants' arsenal of toxic compounds
REPRODUCTION & DEVELOPMENT *
*How do We Know This? Isotope studies of elements present fossil bones and tusks
in microscopic quantities give
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.
(Fisher 1996)(Kerr 2008) (Kurtén & Anderson 1980) (Martin 2005) (Rountrey 2006)
Mortality and Extinction
- Age at weaning, estimated about 5-6 years for one Woolly Mammoth calf (Rountrey 2006)
- Elephant tusks grow continually and absorb carbon and nitrogen isotopes from food.
- Milk is rich in one heavy isotope of nitrogen and low in a heavy carbon isotope when compared with plant food.
- Scientists can thus determine the approximate time when dietary switch occurs
- The long nursing period may reflect the stress of harsh arctic conditions. Columbian mammoths may have nursed for less time.
- Similar to that of African elephant in high-stress environment
- Onset of a male's prime reproductive period may be recorded as a decline in the growth rate of a tusk
around 10-13 years (Fisher 1996)
- Living elephants are similar
- This study done with mastodont tusk; mammoths would probably be similar
- Tusk growth rates of adult females may record periods of pregnancy and nursing. (Fisher 1996)
- Juvenile M. columbi preyed upon by the sabertooth cat, Homotherium
& Anderson 1980)
- 441 milk teeth of mammoth calves found in Freisenhahn Cave, Texas along with saber tooth cat remains
- Starvation, accidents, and human hunters the main causes of death
of adult mammoths
- Old age individuals (between 55 and 70 years) would starve when their last set of teeth were worn down
- Some 20 archaeological sites in North America have Clovis points associated with M. columbi bones.
- Human hunters and climate change are causes most often suggested for the extinction of most of the mammoths around 13,000 years ago. (Martin 2005)
- Recent studies say a comet's impact caused extinction of M. columbi and other large Ice Ages animals; this idea has now been challenged. (Kerr 2008)
DISEASES AND PATHOLOGY*
*How do We Know This? Abnormalities in fossils bones may show
evidence of arthritis, cancer, nutritional stress, fractures and more.
(Gillette & Madsen 1993) (Krzeminska 2008)(Leshchinskiy 2003)
- Pathologies on
mammoth bones, especially vertebrae and limb bones are common.
- One mammoth studied was estimated to be nearly 60 years in age, with arthritic changes in many bones of his body.(Gillette & Madsen 1993)
- Severe arthritis of most vertebrae
- Bone loss of many rib facets
- Bony growths restricting front limb movement
- A woolly mammoth from western Siberia showed degenerative changes in much of its skeleton (Leshchinskiy 2003).
- Woolly mammoth bones from Poland have several pathologies
- Healed fractures
- Malformations of vertebrae, wrist bones, teeth
- Furrows on the cement surface of teeth
- Depressions in bone from abscesses
Important Web Resources (and where to view mammoth fossils in museums):
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