by Susan Lumpkin
The Zoos two Bactrian camels shed in the spring. Great shaggy mats of fur slowly slough off, hanging from the animals like globs of golden brown cotton candy. A thick woolly winter coat is a requirement for an animal that withstands winter temperatures in the Gobi desert as low as minus 40°F. So too is shedding that heavy coatin the desert summer, temperatures soar above 100°Fand replacing it with a lighter one.
The
urge to peel away those messy sheets of wool is almost irresistible,
like the need to peel away chipped paint or sunburnt skin.
And, were we camel herders, we would. Aside from a multitude
of other products and services camels provide, two-humped
Bactrian camels yield 11 to 17 pounds of wool each year, and
some dromedaries, their one-humped cousins, provide four to
nine pounds. People weave the wool into cloth for tents, clothes,
and blankets.
But wool is a minor blessing, a bonus from animals that for centuries have offered people many gifts, from food to fuel and transportation. For instance, camels provide milk. Lots of milk. After giving birth, females can produce more than a gallon of milk a day for nine to 18 months, and camel milk is a major component of the diets of camel herders. Among some Saharan nomads, camel milk, sometimes mixed with camel blood, is virtually the only source of nourishment. Camel milk is also turned into butter and cheese, and fermented to produce an alcoholic beverage. In India, camel milk is believed by some to have medicinal properties, and is prescribed for jaundice, tuberculosis, and asthma. For Westerners raised on cow milk, camel milk may take some getting used to. On a visit to Kenya, I found the cafe au lait camel vile, the cheese only slightly less so, and choked it down out of politeness to my hosts, but slowly, so as to avoid the offer of seconds.
Camel meat is prized too, although animals so valuable for so many other things are generally slaughtered only when they can no longer work, or on special ceremonial occasions. Or, as happened in Mongolia in 1994, when herders killed camels rather than smaller beasts to meet government meat quotas; to stem the loss of camels, the government had to ban camel killing. Camels thick hides are also a resource: They are fashioned into saddles and leather containers. Finally, dried camel dung provides fuel for fires, a significant resource in arid lands where wood is scarce.
Apart
from food and fuel, the camels other great utility is as
a beast of burden. A camel can walk 25 to 30 miles a day,
day after day, while carrying 300 pounds of cargo. Some breeds
can carry more than twice this amount. And they can do this
even in the searing heat or numbing cold of the desert. For
centuries, camels were the vehicles of choice for traversing
arid areas from western Africa to Mongolia and China. Great
camel caravans plied the Silk Route from China through Central
Asia to what is now Iraq. The earliest incense and spice trade
was conducted using camels to carry goods between the markets
of Arabia and the Mediterranean. Just a few hundreds of years
ago, caravans of as many as 120,000 camelsin straggling lines
up to six miles longlinked Middle Eastern cities from Arabia
to Jerusalem. Even today, camels move as much as 30 percent
of the cargo traffic in the Gobi. In North Africa, it is still
often cheaper to move goods by camel than by truck, although
camel caravans are disappearing. Remaining, however, are 3,000-camel
caravans that twice a year carry salt 375 miles from mines
in Taoudenni, Mali, to Timbuktu, which lies in the center
of that northwest African country.
Camels figure in a startling case of cultural reversal. The use of wheels is widely considered an emblem of cultural progress. But starting in the year 300, people from Morocco to Afghanistan began to give up their wheeled vehicleschariots and carts pulled by horses and oxenin favor of more efficient pack camels; by the year 600, wheeled vehicles had been entirely abandoned. Only in the last century did wheeled transport vehicles begin to reappear. In other areas, however, camels were and are used mainly to pull wheeled carts and ploughs; this, in fact, was probably the first and primary reason for the domestication of the Bactrian camel.
With
the proper saddle, a camel can also be ridden like a horse
(as opposed to carrying people as if they were luggage). Soldiers
as well as bandits mounted on riding camels loomed large in
Saharan desert hostilities for about 2,000 years, declining
only after World War I. Arabs conquered the Sahara on camelback,
and, much later, in the early part of this century, French
camel corps "pacified" the Saharan nomads who resisted
French colonial rule.
Bactrians appear not to have been used in battle. Genghis Khan conquered his huge Mongol empire on charging steeds, while camels plodded along carrying the provisions. In Mongolia today, horses are still far more prestigious than camels (caring for horses is mens work while women look after other livestock) and are as culturally important as camels are in the Sahara. Outside of the desert, to which camels are better adapted, horses are superior for riding into combat.
I have some experience with both animals, having ridden a horse and ridden a camel each once, in Montana and Kenya, respectively. On the horse, I felt like an extension of it, sitting solidly on its back and moving to its rhythms. On the camel, the sensation was of floating above it, like taking a ride in a ground-skimming balloon. One sits taller on a camel than on a horse, and sees farther. But I think Id rather go into battle on horseback, and reserve camel riding for sightseeing.
Deserts and DomesticityIn return for all this service from camels, people give camels water when they need it. Despite an impressive array of adaptations for life in the desert, domestic camels do rely on people to provide them with water. But few camels are fed by people (although quite recently wealthier camel owners began to feed their camels). Rather, camels forage more or less freely, getting all of their nourishment from plants, including many salty, dry, or spiny species few other animals will eat.
Under desert conditions, as in the Sahara where there is almost no surface water, camels are dependent on their owners for water, which must be drawn from desert wells. Camels also become attached to a home area, to which they generally return, even from very far away. For this reason, many dromedary camels live in a semi-wild condition, their owners secure in the knowledge that, left to find their own food, camels will still regularly return to familiar wells to have water drawn for them. Even while working, camels generally forage freely, snatching what bites they can while walking slowly and then foraging farther afield during breaks and at night. Guarded camelsthose not allowed to roam unattended by herdersalso largely fend for themselves to find food.
Dromedaries were probably first domesticated 4,000 to 5,000 years ago in southern Arabia, where coastal residents seemed to have subsisted largely on sea cows and a smattering of wild camels. Some authorities speculate that it was shared dependence on a limited number of watering sites in the desert that brought wild dromedary camels and people together. Jonathan Kingdon, noted zoologist and author of Mammals of Arabia, believes that these Arabs domesticated camels in a conscious act of conservation. At the time of domestication, camels, once existing in numerous species across a broad swath of arid Eurasia, were reduced to two species and the dromedary was in rapid decline. The dromedarys demise may have been due to overhunting, or to climate changes at the end of the last ice age that left its range increasingly hot and dry. By about 7,000 years ago, wild dromedaries were found only in southern Arabia and they became extinct there 2,000 to 3,000 years ago. Had those early Arabs not saved the camelsswitched from consuming the meat of hunted camels to drinking the milk of live onesthese extraordinarily useful animals, animals that became a focal point of Arab culture and enabled Arabs to conquer the desert, would have been lost.
From southern Arabia, people slowly distributed dromedaries across the Middle East and North Africa, and during Roman times these camels reached as far as parts of southwestern Europe. In fact, a small number of camels worked in Italy until World War II.
Bactrian camels were domesticated in northern Iran and Turkmenistan about the same time as the dromedaries but these were almost certainly independent events. (Coincidentally, the camels South American relativesllama and alpacawere domesticated at about the same time.) At that time wild Bactrians ranged from Turkey to Mongolia and the domesticate of this cold-adapted animal was adopted throughout this area. About 2,000 years ago, however, a cold-adapted dromedary was developed and came to dominate most of the domestic Bactrians former range. Today, most of the worlds 14 to 17 million domestic camels are dromedaries, and most of these live in Africa. Bactriansabout 2.5 millionare found in Central Asia, where they form just a few percent of the total livestock population. Our knowledge about the two species mirrors the sizes of their populations. Most detailed scientific information about camels pertains to dromedaries.
Unlike dromedaries, Bactrian camels still exist in a wild state, but in very low numbers. Once widely distributed through the Gobi and into China, camel numbers have been declining for 50 years due to competition for food and water with livestock, new roads cut through their once-isolated domain, and hunting. Today, perhaps 1,500 survive (although estimates range from a few hundred to several thousand), most in Mongolias 17,000-square-mile Great Gobi Strictly Protected Area, which was established for their conservation in 1976. Wild camels also hang on in China, particularly in a desolate area around a dried-up lake called Lop Nur, near a former nuclear-testing site. The remoteness and hostility of the habitats has kept most people out of these sanctuaries. Still, the camels remain threatened by hunters, and by herders and miners moving inexorably into the desert, where they occupy the oases and thus deny access to water to the profoundly shy wild camels.
Wild Bactrians were unknown to Western scientists until 1877, when the Russian biologist-explorer Nikolai Przewalski, known also for "discovering" the wild horse called Przewalskis horse, or tahki (see ZooGoer September/October 1997), saw them in China. And whether this wild population was ancestral to the domestic form or consists merely of escaped domestics gone feral had been the subject of some debate until recent genetic analysis confirmed that the wild and domestic populations are distinct. The two differ in appearance. The wild form is smaller, slimmer, and narrowerits Mongolian name. havtagai, means flatand has smaller, neatly conical humps compared to the big floppy humps of the domestic.
Saving Every Drop
Every schoolchild knows there are two kinds of camels: one-humped and two-humped. We call all one-humped camels dromedaries (from Camelus dromedarius), a word from the Greek for "rode" that was once applied only to camel breeds used for riding and racing. Two-humped camels are called Bactrians (Camelus bactrianus), a reference to an ancient countryBactria in southwestern Asiawhere these camels were once wrongly believed to have been domesticated. The two species do interbreed, and interbreeding may have contributed to the development of cold-adapted dromedaries noted earlier.
No one knows when camels humps first evolved, but one-humped varieties may have evolved from two-humped species in the hot, dry climates of Arabia. A single hump has a smaller surface area from which to absorb heat and lose water than a double one. Whether one or two, humps have the same function. Camels store fat (not water!) in their humps, which they burn during periods of food scarcity or during extended bouts of hard work when they are given little time to feed. The fat-filled hump may also slow the conduction of heat from the sun to the delicate internal organs.
Its not surprising that so many people believed humps stored water. Camels can go without drinking water longer than any other domestic animal. During the cool winter season in the Sahara, for instance, camels get all the water they need from the plants they eat and thus may go six or seven months without drinking. During the summer, camels need drinking water but even at the hottest daytime temperatures in the Sahara, which may exceed 118oF, camels drink only every five days. When temperatures range between 85°F and 95°F, drinking at 10- to 15-day intervals is typical. During each watering bout, however, camels quickly drink huge amounts of waterup to 50 gallons in a few hourswhen theyve gone five to seven days without. (The herders job of watering camels is thus serious work; imagine drawing that amount of water from a well for dozens of camels.)
Camels can go so long without water because they lose it very slowly and can withstand high rates of dehydration that may result in the loss of more than 30 percent of their body weight. A 12-percent water loss leaves a person, for example, near death, while a 15-percent loss is lethal to most mammals. Camels save water by producing dry feces and only small amounts of urine. More important, the camels body temperature rises with the daytime ambient temperature to as high as about 104°F. Matching the ambient temperature prevents sweating because the animals arent hot. Body temperature then falls as its surroundings cool in the evening. Camels do have sweat glands; however, sweat evaporates under the fur, where it provides the maximum body cooling. (This is why camels are shorn only in milder, semi-arid areas such as northern Kenyashorn camels lose far more water than those from which wool is collected as it sheds naturally.)
Camels also minimize water loss through behavior: They rest as much as possible or allowed during the day (camel caravans often traveled only at night during the summer), huddle in whatever shade is available, use each other for shade, and even sit or stand facing the sun, a posture that exposes as small a surface as possible to the burning rays.
Its all the more shocking then to witness a male camel in rut. Like a miser who suddenly starts throwing dollars into the wind, a rutting male wastes water prodigiously. To court females and intimidate rivals, rutting males drool and spit and urinate like leaky fountains. They reek of an oily secretion that flows copiously from scent glands on their napes. This seems to me to be a perfect example of Israeli biologist Amotz Zahavis "Handicap Principle" of sexual selection, developed to account for the evolution of male traits, such as a peacocks long tail, that have no survival value—may indeed be counter-productive to survival—but are attractive to females. Applied to camels, the Handicap Principle suggests that those dripping males are saying, "Im so strong I can afford to waste water and still be fine, so mate with me and your sons and daughters will be equally strong." The message to male rivals may be similar: "Im really tough so dont mess with me."
Adaptations to conserve water and to survive on poor vegetation make it possible for camels to live in harsh desert environments, but not without human help at the well. In return, camels have made it possible for people also to live in such environments. The relationship between camels and people is truly mutualistic. In talking about the camel nomads of the western Sahara in their book The Camel, Hilde Gauthier-Pilters and Anne Innis Dagg said, "The hard living conditions...forge a close bond between animals and men, probably closer than that in any other culture." This bond is partly revealed in the vocabulary of Saharan nomads, which boasts about 700 different words for describing camels.
The forces of modernization, however, may soon spell an end to nomadism and camel-human mutualism. In Arabia, where domestic dromedary camels originated, a diminishing number of camels are now kept largely for pleasure and prestige. On the other hand, camels have become increasingly important in semi-arid areas, such as northern Kenya and Pakistan, where they are more efficient milk and meat producers than cattle and cause less environmental degradation.
In Covenant with the Wild: Why Animals Chose Domestication, Stephen Budiansky argues that "...in an evolutionary sense, domesticated animals chose us as much as we chose them." He believes that animals became domesticated only because living with people and providing us services was essentially a better dealresulting in greater reproductive and thus evolutionary successthan living wild. For camels, this argument carries some weight. With the ancestors of dromedaries extinct, and those of Bactrians on the verge, the domestic forms continue to thrive.
ZooGoer 28(2) 1999. Copyright 1999 Friends of the National Zoo. All rights reserved.
