Camels (extant/living species; Camelus spp.): Taxonomy & History

Dromedary camel

• First classified by Linnaeus as Camelus dromedarius in 1758
• Common names
  • Dromedary
  • Arabian camel
  • One-humped camel
• Word origins
  • From Greek dromas "running" (Arabian camels were bred and trained for riding)
  • Early variant - drumbledairy (1560s) (Harper, 2012)

Domestic Bactrian camel

• First classified by Linnaeus as Camelus bactrianus in 1758
  • Typically wild animal named first, but Linnaeus only knew of domestic camels
• Common names
  • Bactrian camel
  • Two-humped camel
• Word origins
  • Camel - Latin camelus from Greek kamelos, from Hebrew or Phoenician gamal; perhaps related to Arabic jamala "to bear" (Harper, 2012)
  • Bactrian - for Bactriana region of ancient Persian Empire (Franklin 2011; Bulliet, 1990)
    • Latin bactriana from Persian bakhtar "the west"
    • Camel caravans transported goods through this northwestern region of modern-day Afghanistan via major trade routes, including the Silk Road

Wild Bactrian camel

• Taxonomic history
  • Discovered by Przewalski in 1878, named Camelus ferus
  • C. ferus confirmed in 2003 by International Commission on Zoological Nomenclature; recognized by the IUCN
  • DNA analysis confirmed that C. ferus should be considered a separate species from the domestic Bactrian camel (Silbermayr, 2009)
    • Ming et al. (2017) confirm two distinct lineages: wild and domestic Bactrian camels
    • Grubb (2005) considered it to be a sub-species, C. bactrianus ferus, contrary to most authors (Hare 2005)
• Word origins
  • From Greek ferus "wild"

• Camelidae family: origins
  • Camelids originated in North America during Eocene, 40-45 million years ago (Cui et al., 2007)
    • Appeared in middle Eocene in North American mountains/plains/deserts (Franklin, 2011)
    • Earliest camelids similar to modern guanaco but rabbit-sized (30 cm at shoulder) (Franklin, 2011)
    • One of most common ungulates in N. America by late Eocene and Oligocene (24-36 million years ago) (Franklin, 2011)
• Camelid tribes: four emerged, two survived
  • Camelini and Lamini diverged about 11-25 million years ago
    • DNA evidence dates the split to 25 million years ago (Cui et al., 2007)
    • Fossil record dates the split to 11 million years ago (Webb 1974; Harrison 1979)
  • Only Camelini and Lamini tribes survived worldwide climactic changes at end of Miocene
    • Camelini (wild and domestic Bactrian camels and dromedaries)
      • Old World (Asia, Middle East, Arabia, North Africa)
    • Lamini (lamas, alpacas, vicuñas and guanacos)
      • New World (South America)
• Migration: two major waves (Webb, 1974)
  • About 3 million years ago (late Tertiary):
    • Camelini migrated across Bering land bridge into Asia
      • Across dry belt of Eurasia, into India
    • Lamini migrated to mountains of South America
  • Both tribes became extinct in North America
• Modern camelid species
  • Unclear evolutionary relationship between C. bactrianus, C. dromedarius, and C. ferus
  • DNA studies show wild Bactrian Camel not ancestor of two domesticated species as previously thought
    • C. ferus is separate lineage and not direct progenitor of C. bactrianus (Ji et al, 2009)
  • Bactrian camels and dromedaries diverged about 5-8 million years ago (Cui et al., 2007; Franklin, 2011)
    • No evidence to indicate that Bactrian camels were ancestor of dromedaries (Kinne et al, 2010

• Bactrian camels
  • Domesticated about 4,000-6,000 years ago in steppes of eastern central Asia (Peters & von Driesch, 1997; reviewed in Groeneveld et al., 2010)
• Spread to Asia Minor ca. 4000 BC, Middle East ca. 2000 BC, China ca. 400 BC (Peters & von Driesch, 1997)
• Currently 16 Bactrian camel breeds (FAO, 2008)
• Dromedaries
  • Domesticated about 4,000-5,000 years ago (Peters & von Driesch, 1997; reviewed in Groeneveld et. al., 2010)
  • Currently 97 dromedary breeds (FAO, 2008)
• Wild Bactrian camels
  • Unclear how they avoided domestication
    • Possibly due to isolation in the Gashun Gobi (Lop Nur) area and Mongolia
    • Perhaps instinctive shyness played a role
• Hybrids (reviewed in Bulliet, 1990)
  • Bactrian camel-dromedary hybrid (bukht)- single long hump
    • First generation larger and stronger than either parent (hybrid vigor)
  • Camel-llama hybrid (cama)(Jones et al., 2008)
    • Female llama fertilized with camel sperm at Camel Reproduction Centre (Dubai)

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia (Linnaeus, 1758) - mammals

Order: Artiodactyla* (Owen, 1848) - even-toed hoofed animals: includes pigs, sheep goats, cattle, deer

Family: Camelidae (Gray, 1821) - camels

Genus: Camelus (Linnaeus, 1758) - camels

Species: Camelus dromedarius (Linnaeus, 1758) - dromedary or one-humped camel
Species: Camelus bactrianus (Linnaeus, 1758) - domestic Bactrian camel
Species: Camelus ferus (Przewalski, 1878) - wild Bactrian camel

*Anatomical and DNA evidence on the relationship between Artiodactyla (even-toed ungulates) and Cetacea (whales and dolphins) led to a merging of the two orders into a new group, Cetartiodactyla (Montgelard, 1997; reviewed in Kulemzina, 2009). As of October 2012, experts had not agreed on whether to define Cetartiodactyla as an official taxonomic order that would replace Artiodactyla and Cetacea. Some continue to list hippopotamuses in the order Artiodactyla (Franklin, 2011) or use the term Cetartiodactyla without defining it as an order (IUCN, 2008).

Sources: Hare (2008), Ming et al. (2017)

Dromedary camels were domesticated about 4,000-5,000 years ago. There are almost 100 breeds.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Bulliet (1990)
Cui et al. (2007)
FAO (2008)
Hare (2008)
Harper (2012)
Kohler-Rollefson (1991)
Kadwell et al. (2001)
Gentry (2004)
ICZN (2003)
Marin et al. (2007)
NCBI (2012)
Price (2005)