mechanization. Its biology goes considerably beyond the mereby Theodo - PDF document

mechanization. Its biology goes considerably beyond the mereby Theodore H. SavoryScientific American Offprint, December 1970Late in the 19th century the Ameri-said of his Democratic opposition: ÒThepride of ancestry or hope of posterity.Óunfair and inaccurate. It is unfair be-enough to afford the offspring a genuinepride of ancestry. It is inaccurate be-duce foals. Donnelly was also gratu-itously unkind: few of the hybrids cre-The origin of the mule is difficult toSo is the breeding of the hinny: the off-donkey as the royal beast. We read in IISam. (13:29): ÒThen all the kingÕs sonshis mule, and fled.Ó The animal was well conjure up the animals inrival of mules from Henetia in Asia Mi-nor, where breeding them was a localspecialty. Mules were also bred inas draft animals and in farming. In laterthe Peloponnesus, particularly in Arcadia,for more than S0 years. The Greek word Mules were cosmopolitan animalsas A.D. 1274 Marco Polo praised theTurkoman mules he encountered incentral Asia. By the 18th century thedustry in Italy, Spain and France. Forwere bred. Heavydraft mules were inbreed of stud donkey, which had un-high favor. The French distinguish be-). Two otherlanguage by the mule industry. TheIn America and Britain the mule was18th century. In Britain the chief de-Among the first in America to encour-Washington, who had been given apound,Ó by the king of Spain. In 1786Washington advertised the animalÕsCompoundÕs stud fee for servingtry, foreseeing the value of mules to theAmerican farmer, chose this practicalsubsequently brought to America fromSpain. In the decade between 1850redity, experimental hybridists failed toacteristics. Hence the mule was the sub-female to its offspring was negligible andmust be critically selected. In contrast,tail. Spanish donkeys, frequently usedmule has the appearance of a horseÕsbody mounted on the legs of an ass. Thehooves as the studs in Poitou. Anotherfour feet and five feet 10 inches). Theare shaped like those of a horse. Themane all resemble a donkeyÕs. Like thelegs of the donkey, the muleÕs legs do horses. The mule brays like a donkey.admirable qualities. It is courageous andand hunger better than the horse. Suchby a few minor drawbacks. The mule isthis respect it differs from the horse andresembles its male parent. It will notmeets them with instant rebuff. The com-how well known is the animalÕs majormeans of protest. The mule can also bemule.Ó Like their masters, however,they have been badly brought up. TheyThe hinny, the hybrid of a femalefor its lesser value. Its distinctive char-acter was known to Pliny, who describedrestrained and slow of movement.Ó Theits male parent. Never as popular as themore than elsewhere. It has greatpack work, draft work and riding. Thewith each role. The largest mules bred,riding. Harnessed for draft work, themule is not at its best before the plow,oxen. Teams of mules, however, are ef-snows of Antarctica to the superheateddesert of Death Valley. FAMILIAR HYBRID, the mule is the offspring of a female horse that has beenmated with a male donkey. Mules resemble their male parent in size and shape ofears, legs and hooves, shape of tail and shortness of mane. Mules can range betweenLESS FAMILIAR HYBRID, the hinny is the offspring of the reciprocal cross, themating of a female donkey with a male horse. Hinies are more horselike in appear-ance than mules. Far less frequently bred than mules, they are long-lived animals POSSIBLE CROSSES between horses and donkeys are indicated in this diagram, along with the natural (black) or hybrid (color) offspring to be expected from each cross. The genotypes and gametes of the parents are also shown. In addition to the sex-determand Y chromosomes, the nonsex chromosomes are indicated by the letter for the horse and the letter for the donkey. Male mules and PARENTPARENT GENOTYPE: AAXYGAMETES: AX AYFemale: AHXXMale: AHXYGENOTYPE: AAXXGAMETES: AX AXFemale: AHXXMale: AHHYFemales: AAXXMales: AHHYGENOTYPE: AHXXFemale: AHXXMale: AJHYGENOTYPE: AHXXGAMETE: AXFemale: AAXXMale: AAXY come into their own. Starting when18 or 20. Carefully loaded, a mule canmally covers 20 to 25 miles in a dayÕsmarch. When the animals areter. During the Indian wars in theAmerican Southwest a number of muleendurance records were set. In 1882set out from the San Carlos Agency inhad covered 280 miles. During thethat same year, a company of the Thirdthe record for a dayÕs march set theor driven. Driving is usually the betterway; the muleÕs hearing is acute, andit is readily controlled by voice. Thusit is said, ÒYou can talk to a horse, butIn the American West both the acute-ing. An experienced mare, a bell slungthe trail. The mare dominated the mules,The muleÕs small hoves give it a sure-ous terrain. This was one reason for theforces in India. As readers familiar withKiplingÕs poem ÒScrew-gunsÓ will remem-ber, they were the usual means of trans-port for the light artillery. They were of-ten shod as horses are. The custom ofis at least as old as ShakespeareÕs day.of recovery after strenuous effort. If adayÕs work has pushed it close to the limitof its strength, a nightÕs rest seems toit ready to undertake another dayÕs la-bor. In this respect the mule is quite dif-ferent from the horse. The muleÕs ad-anatomy of its hindquarters. This mus-mentally need the same care. Althoughjected to the rigors of active service. Aerably for mules of a different type andin different circumstances.mule. Among other things, the readerbacks. The pages included informa-emergencies of service. Perhaps withmules. Nor is the humanitarian touchomitted: ÒWhen unsaddled,Ó the in-oughly enjoy.Óhistory of Antarctic exploration is famil-Scott and his party, but few rememberthat reached ScottÕs tent were drawnfrom India to Ross Island in 1912. Theyney, each mule pulling a sledge load of700 pounds. They soon showed thewhen disturbed. It is recorded that theytimes ate sugar, tea leaves and tobaccoash. On one occasion two of them SELECTED FEATURES of equid anatomy are indicated on this outline drawing of amule. The mule differs from the horse in its donkey-like appearance and in lacking the their endurance and dying. The otherJanuary,1913.During World War I many menwhich they always respond. Their ser-mule.Ó The others responded to theirdier accepted with good humor. Such cartoon in 1916 showing a groupof tethered mules. The animals are de-ian, then on a staff officer and finallyon the regimental commander.region. The time came not long agoof a Royal Field Artillery battery manyyears ago. On each occasion the vet-erinary officer, emphasizing his adviceWater your mules first.ÓPerhaps the officer did not noticeabove, comes near to being poetry. ItA more conscious poetic effort in-. The scene comesThe lines, as rendered by A. T. Murray,mules; And ever upward, downward,accents: Polla dÕananta katantasterility of the male mule? In 1913 H.that gives rise to germ cells. Specifi-gether. Male mules and male hinniesresulted in offspring. As a matter of fact,without hope of posterity.Female mules, however, are lessceive. Conception is usually followedried to its full term of 10.5 months. The (Òwhen a mule foalsÓ), whichblue moon.Ó Such occasional foals areof two kinds. If the sire was a donkey,ther.hinnies in existence. Served by aing. Served by a donkey, she bears atypical donkey.they represent a general truth. If oneever, the reproductive pattern can beof the donkey by A. When the sex chro-mosomes X and Y are added, a genetickeys will be AAXY and AAXX. TheAHXY (male). The breeding of hinnieswould be written: AAXXX HHXY=AHXX (female) or AHXY (male).AHXX, with the offspring either AHXX,AHXY,HHXX or HHXY, which is to sayboth sexes of mules and horses. Thether AHXX or AHXY, that is, either ofnot present in female mules. This leads Similarly, the absence of horses fromcontain only donkey chromosomes. AllAll of this does not, however, ex-mulelike). The probable truth is thatarisen too seldom. Unlike fruit flies orics. They breed too slowly, they pro-duce only one offspring at a time evenfor research purposes. These consid-individual mule or hinnyÕs being the off-To complicate matters further, it is ahas served a female donkey, it is oftenand transportation. This trend will un-doubtedly continue. Worldwide mule-the U.S. are indicative. In 1920 the1954 to 1.6 million. A graph of theselie on a straight line, indicating the com-sometime around 1958. This has notunmistakable. In many ways it will beregrettable. Mules have played a wor-thy role in human affairs over much of TWENTY-MULE TEAM hauls two freight wagons and a tank wangon in train through the forbidding terrain of Death Valley in Califor-nia. The freight wagons are 16 feet long; their rear wheels are seven feet in diameter. Each weighs nearly four tons and can of cargo. The water tank holds 1,200 gallons. The 20-mule teams were used in the 1880Õs to carry borax from Death Valley to tat Mojave, 165 miles away. The United States Borax & Chemical Corporation uses the team as its trademark..UNITED STATES BORAX & CHEMICAL CORPORATION TWENTY-MULE TEAM