The one-humped camel (Camelus dromedarius ) is found in
the Arabian deserts, while the two-humped camel
(Camelus bactrianus ) is an Asiatic animal.
All camelids are similar, in having 37 pairs of chromosomes. The Old World camels may be
crossed,
producing fertile offspring. (New World camelids can be crossed with each other with
similar results.) Despite some major differences in size, all of the camelids
are basically similar
in structure. Because camelids evolved in a semi-desert environment, they have developed
sophisticated
physiological adaptations for coping with both heat and dehydration.
Bactrian Camels
These camels are thought to have been domesticated prior to 2500 B.C.
(The name Bactrian is derived from a place name, Baktria, on the Oxus
River in northern Afghanistan. This is pretty strange, since the
domesticated form of this camel didn't originate there, nor is it found
there currently.) Domesticated Bactrian camels were found in southern
Russia by 1700 - 1200 B.C. and even in western Siberia by the 10th
century B.C. They were used in China as early as 300 B.C. as the
original "silk route" camels, but were replaced by crossbreeds of the
Bactrian/dromedary later on.
Dromedaries
These camels were domesticated even earlier than the Bactrians, before 3000 B.C. in the
Arabian penninsula. The term "dromedary" is derived from the dromos (Greek for
"road") and thus
is directly applicable only to the racing or riding dromedary. However, the term is used
throughout the
world to describe this species. Dromedaries were first associated with nomadic Semitic
cultures and did not
become important until the rise of the Arabian culture. They became important domestic
animals
only with the Moslem conquests of Egypt in the 7th to 11th centuries A.D.
Dromedary's adaptation to heat and dehydration
This camel does not store water any more than does any other species, yet it does
not need to drink
water for days. It can handle extreme dehydration as a result of a number of different
physiological adaptations.
Camels have been known to lose safely body water equivalent to 40% of its body weight, a
loss that
would be lethal in any other animal.
Information on Camels came from the Book: Medicine
and Surgery of South American Camelids (Llama, Alpaca, Vicuna, Guanaco) by
Dr. Murray E. Fowler.
The first chapter, as well as other sections, of this book deals with general
biology and evolution of camelids, and thus touches on camels, their Old
World "cousins". Info gathered at llamaweb.com/camel.
