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Brief Summary

    Elephantidae: Brief Summary
    provided by wikipedia

    Elephantidae is a family of large, herbivorous mammals collectively called elephants and mammoths. These are terrestrial large mammals with a snout modified into a trunk and teeth modified into tusks. Most genera and species in the family are extinct. Only two genera, Loxodonta (African elephants) and Elephas (Asiatic elephants), are living.

    The family was first described by John Edward Gray in 1821, and later assigned to taxonomic ranks within the order Proboscidea. Elephantidae have also been revised by various authors to include or exclude other extinct proboscidean genera.

    Brief Summary
    provided by EOL authors

    Taxonomy

    Elephantidae (the elephants) is the single family with living representatives in the mammal order Proboscidea. Wittemyer (2011) recognized three living elephant species: Asian Elephant (Elephas maximus), African Forest Elephant (Loxodonta cyclotis) and African Savanna Elephant (Loxodonta africana). However, Wittemyer notes that some authorities believe just a single African Elephant species should be recognized, with the forest and savanna forms recognized only as subspecies. African Savanna Elephants are the largest terrestrial animals on Earth.

    Morphology

    The most distinctive feature of elephantids and their extinct proboscidean relatives is the trunk, which is derived from the nose and upper lip. The African Elephant has two fingerlike projections at the end of its trunk whereas the Asian Elephant has just one. The trunk is very powerful, but also very sensitive and its opposable lips can grasp and manipulate very small items such as single nuts. In addition to manipulating objects, the trunk is also used for breathing, olfaction, touch, and sound production.

    The ivory tusks of elephants are enlarged second incisors. Both male and female African Elephants have fully developed tusks, although tusk size varies geographically (in Asian Elephants, only males have fully developed tusks). In some areas, selection from hunting pressure by humans appears to have resulted in decreased average tusk size and an increase in the frequency of tusklessness.

    The large ears of African Elephants play an important role in thermoregulation.

    African and Asian Elephants differ in numerous ways, including body size, absolute and relative size and shape of ears, tusks, trunk structure, number of ribs, and number of toenails on the front and hind feet. In addition, relative to African Elephants, Asian Elephants tend to have smoother skin and more hair.

    Behavior and Ecology

    Elephants swim well and are able to submerge themselves and use the trunk as a breathing tube. Among the diverse communication modalities used by elephants is infrasonic communication, which elephants were discovered to utilize only in the late 20th century. The long wavelengths of infrasound are able to travel across large distances, with communication feasible across perhaps as much as 10 km under ideal conditions, although individuals can apparently be distinguished only up to one or a few kilometers. Evidence suggests that seismic signaling may also be used by elephants.

    Elephants have a very complex social structure and young animals stay with their mother and her group for many years (perhaps for their entire lives). African Savanna Elephants typically stay within a few meters of their mothers for the first 4-8 years of life. Both Asian and African bulls are typically independent of their families by around 15 years (sometimes as young as six years).

    Elephants spend as much as three quarters of their time feeding. Elephants both graze (feeding on grass) and browse (feedingmainly on leaves and terminal twigs of woody plants) and the diet composition may shift dramatically between wet and dry seasons. Asian Elephant diets tend to include more grass than those of African Elephants.

    Elephants can thrive in habitats ranging from deserts to rainforests. They play major roles in shaping ecosystems through their consumption of shrubs and trees and as seed dispersers.

    In recent times, African Elephants have been distributed from southernmost South Africa to the Sahel. In Roman times, they were present even in the northern Mediterranean region. Today, most African Elephants live in the sub-Saharan savanna and dry woodland ecoregions, but they continue to persist in desert regions such as Mali's Sahel and the Namib. In addition, they are found in dense tropical forests such as those found on East Africa's volcanos. Historically, Asian Elephants occupied a broad range in tropical Asia from Iraq, India, and Sri Lanka to Malaysia, Indonesia, and southern China. Today, they have been extirpated from more than 85% of this range and over 60% of Asian Elephants are thought to reside in India. Other remnant populations are found in Sri Lanka, Burma, Thailand, and the larger islands of the Malay Archpelago.

    Elephants and Humans

    The lives of elephants and humans have been intertwined for millenia. Asian Elephants were domesticated in the third millenium BC in the Indus Valley and this likely drove the first major declines of the species. Ivory has been a major focus of human-elephant interactions for thousands of years. Given that only the males of Asian Elephants bear tusks, African ivory was needed to satisfy the demand in India, China, and Japan and was being traded by the 6th century BC. The African slave trade was closely tied to the ivory trade, with slaves carrying ivory to the coast, where both were sold. Elephants were eradicated from much of west and southern Africa during this period. With the decline of the slave trade, ivory trade also declined and elephant populations are thought to have rebounded during much of the 1900s. Unfortunately, the 1970s saw a huge upsurge in the ivory trade with a devastating impact. It has been estimated that between 1979 and 1989 the African Elephant population was reduced from around 1.3 million to around half a million. Since then, there have been periods of both recovery and decline and the status of African Elephants remains precarious. As large-scale agriculture has increased in Africa since the 1980s, human-elephant conflicts over crop-raiding have increased. Asian Elephant populations have continued to decline as a result of both the ivory trade and habitat loss/range reduction. Although young elephants can fall prey to Tigers (in Asia) and Lions (in Africa), adult elephants are safe from predators except for humans.

    At one time, elephants ranged over much of Africa and southern Asia and into the Middle East. Demand for ivory by the Roman Empire is thought to have led to the eradication of African Elephants from the northern Sahara and Asian Elephants from the Middle East. Elephant populations in both Africa and Asia declined with the increased demand for ivory (notably, for piano keys in the 1800s and 1900s). Range reduction and fragmentation poses a serious threat to the long-term viability of elephant populations in both Africa and Asia. From the vantage point of the early decades of the 21st century, only in southern Africa do elephant populations appear relatively secure, but elephants have shown themselves to be highly adapable and with adequate protection there is still hope for recovery over much of their current range. If the ivory trade increases, this will pose a great threat to remaining elephant populations, especially in light of the political instability in many of the countries in which elephants persist. Counterbalancing these threats, however, is the growing economic importance of ecotourism in many countries with elephants.

    (Wittemeyer 2011 and references therein)

Comprehensive Description

    Elephantidae
    provided by wikipedia

    Elephantidae is a family of large, herbivorous mammals collectively called elephants and mammoths. These are terrestrial large mammals with a snout modified into a trunk and teeth modified into tusks. Most genera and species in the family are extinct. Only two genera, Loxodonta (African elephants) and Elephas (Asiatic elephants), are living.

    The family was first described by John Edward Gray in 1821,[3] and later assigned to taxonomic ranks within the order Proboscidea. Elephantidae have also been revised by various authors to include or exclude other extinct proboscidean genera.

    Classification

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    "Man, and the elephant" plate from Hawkins A comparative view of the human and animal frame, 1860
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    Skeleton of Mammuthus meridionalis at MNHN

    Scientific classification of Elephantidae taxa embraces an extensive record of fossil specimens, over millions of years, some of which existed until the end of the last ice age. Some species were extirpated more recently. The discovery of new specimens and proposed cladistics have resulted in systematic revisions of the family and related proboscideans.

    Elephantids are classified informally as the elephant family, or in a paleobiological context as elephants and mammoths. The common name elephant primarily refers to the living taxa, the modern elephants, but may also refer to a variety of extinct species, both within this family and in others (see Elephant (disambiguation)). Other members of the Elephantidae, especially members of Mammuthus, are referred to by the common name mammoth.

    The family diverged from a common ancestor of the mastodons of Mammutidae. The classification of proboscideans is unstable and has been frequently revised.

    The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on hyoid characteristics:[1] .mw-parser-output table.clade{border-spacing:0;margin:0;font-size:100%;line-height:100%;border-collapse:separate;width:auto}.mw-parser-output table.clade table.clade{width:100%}.mw-parser-output table.clade td{border:0;padding:0;vertical-align:middle;text-align:center}.mw-parser-output table.clade td.clade-label{width:0.8em;border:0;padding:0 0.2em;vertical-align:bottom;text-align:center}.mw-parser-output table.clade td.clade-slabel{border:0;padding:0 0.2em;vertical-align:top;text-align:center}.mw-parser-output table.clade td.clade-bar{vertical-align:middle;text-align:left;padding:0 0.5em}.mw-parser-output table.clade td.clade-leaf{border:0;padding:0;text-align:left;vertical-align:middle}.mw-parser-output table.clade td.clade-leafR{border:0;padding:0;text-align:right}

    Elephantidae ElephantinaeLoxodontini

    Loxodonta (African elephants)Elephant white background.png

        ElephantiniPalaeoloxodontina

    PalaeoloxodonElephas-antiquus.jpg

        Elephantina

    Elephas (Asian elephants)Indian elephant white background.jpg

       

    Mammuthus (Mammoths)Mammuthus trogontherii122DB.jpg

             
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    The most accurate phylogenetic tree of the elephants and mammoths as of 2010

    The systematics of the living subspecies and species, the modern elephants, has undergone several revisions. A list of the extant Elephantidae includes:[4]

    Elephantidae
    Loxodonta (African)
    L. africana African bush elephant
    L. a. pharaoensis North African elephant
    L. cyclotis African forest elephant
    Elephas (Asiatic)
    E. maximus Asian elephant
    E. m. maximus Sri Lankan elephant
    E. m. indicus Indian elephant
    E. m. sumatranus Sumatran elephant
    E. m. borneensis Borneo elephant
    E. m. sondaicus Javan elephant
    E. m. asurus Syrian elephant

    Evolutionary history

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    Evolution of elephants from the ancient Eocene (bottom) to the modern day (top)

    Although the fossil evidence is uncertain, by comparing genes, scientists have discovered evidence that elephantids and other proboscideans share a distant ancestry with Sirenia (sea cows) and Hyracoidea (hyraxes).[5] These have been assigned with the demostylians to the clade Proboscidea. In the distant past, members of the various hyrax families grew to large sizes, and the common ancestor of all three modern families is thought to have been some kind of amphibious hyracoid.[citation needed] One hypothesis is that these animals spent most of their time under water, using their trunks like snorkels for breathing.[6][7] Modern elephants have this ability and are known to swim in that manner for up to six hours and 50 km (31 mi).

    In the past, a much wider variety of genera and species was found, including the mammoths and stegodons.[8][9]

    See also

    References

    1. ^ a b Shoshani, J.; Ferretti, M. P.; Lister, A. M.; Agenbroad, L. D.; Saegusa, H.; Mol, D.; Takahashi, K. (2007). "Relationships within the Elephantinae using hyoid characters". Quaternary International. 169-170: 174. Bibcode:2007QuInt.169..174S. doi:10.1016/j.quaint.2007.02.003..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
    2. ^ Maglio, Vincent J. (1973). "Origin and Evolution of the Elephantidae". Transactions of the American Philosophical Society. 63 (3): 16. JSTOR 1006229.
    3. ^ Gray, John Edward (1821). "On the natural arrangement of vertebrose animals". London Medical Repository. 15: 297–310.
    4. ^ Shoshani, J. (2005). "Order Proboscidea". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
    5. ^ Ozawa, Tomowo; Hayashi, Seiji; Mikhelson, Victor M. (1997-04-24), "Phylogenetic Position of Mammoth and Steller's Sea Cow Within Tethytheria Demonstrated by Mitochondrial DNA Sequences", Journal of Molecular Evolution, 44 (4): 406–413, Bibcode:1997JMolE..44..406O, doi:10.1007/PL00006160, PMID 9089080
    6. ^ West, John B. (2001), "Snorkel breathing in the elephant explains the unique anatomy of its pleura", Respiratory Physiology, 126 (1): 1–8, doi:10.1016/S0034-5687(01)00203-1, PMID 11311306
    7. ^ West, John B.; Fu, Zhenxing; Gaeth, Ann P.; Short, Roger V. (2003-11-14), "Fetal lung development in the elephant reflects the adaptations required for snorkeling in adult life" (PDF), Respiratory Physiology & Neurobiology, 138 (2–3): 325–333, doi:10.1016/S1569-9048(03)00199-X
    8. ^ Todd, N. E. (2001). African Elephas recki: time, space and taxonomy Archived 2008-12-16 at the Wayback Machine. (pdf). In: Cavarretta, G., P. Gioia, M. Mussi, and M. R. Palombo. The World of Elephants, Proceedings of the 1st International Congress. Consiglio Nazionale delle Ricerche. Rome, Italy.
    9. ^ Todd, N. E. (2005). Reanalysis of African Elephas recki: implications for time, space and taxonomy. Quaternary International 126-128:65-72.

    Comprehensive Description
    provided by EOL authors
    Elephants have the largest cerebral cortex of all terrestrial animals.

Systematics or Phylogenetics

    New Phylogenetic Analysis of the Family Elephantidae Based on Cranial-Dental Morphology - Todd - 2009 - The Anatomical Record - Wiley Online Library
    provided by EOL authors

    New Phylogenetic Analysis of the Family Elephantidae Based on Cranial-Dental Morphology

    Nancy E. Todd

    Article first published online: 20 NOV 2009

    DOI: 10.1002/ar.21010

    Copyright © 2009 Wiley-Liss, Inc.

    The Anatomical Record Volume 293, Issue 1, pages 74–90, January 2010

    Abstract: In 1973, Vincent Maglio published a seminal monograph on the evolution of the Elephantidae, in which he revised and condensed the 100+ species named by Henry Fairfield Osborn in 1931. Michel Beden further revised the African Elephantidae in 1979, but little systematic work has been done on the family since this publication. With addition of new specimens and species and revisions of chronology, a new analysis of the phylogeny and systematics of this family is warranted. A new, descriptive character dataset was generated from studies of modern elephants for use with fossil species. Parallel evolution in cranial and dental characters in all three lineages of elephants creates homoplastic noise in cladistic analysis, but new inferences about evolutionary relationships are possible. In this analysis, early Loxodonta and early African Mammuthus are virtually indistinguishable in dental morphology. The Elephas lineage is not monophyletic, and results from this analysis suggest multiple migration events out of Africa into Eurasia, and possibly back into Africa. New insight into the origin of the three lineages is also proposed, with Stegotetrabelodon leading to the Mammuthus lineage, and Primelephas as the ancestor of Loxodonta and Elephas. These new results suggest a much more complex picture of elephantid origins, evolution, and paleogeography. Anat Rec, 2010. © 2009 Wiley-Liss, Inc.

Education Resources

Citizen Science links

    Information resources on elephants
    provided by EOL authors

    see alsohttp://www.nal.usda.gov/awic/pubs/elephants/elephants2.htm

    AWIC Resource Series No. 18 - April 2003

    Updated by Information Resources on Elephants, 2010

    Compiled by: Richard L. Crawford, D.V.M.,D'Anna Jensen, B.S., LATG, &Tim Allen, M.S.

    Animal Welfare Information Center ,National Agricultural Library,U.S. Department of Agriculture

    Published by: U. S. Department of Agriculture Agricultural Research Service

    National Agricultural Library Animal Welfare Information Center

    Beltsville, Maryland 20705

    Contact us: http://www.nal.usda.gov/awic/contact.php

    Web site: www.nal.usda.gov/awic

    Published in cooperation with the Virginia-Maryland Regional College of Veterinary Medicine