MULES THAT BREED 
Occasional Cases Reported, Some of Them with Good Evidence—Two Recent 
Cases in America—Studies of Germ-Cells Indicate that Chance of 
Mule Breeding is Very Slight 
ORREN Lioyp-JONES 
Associate Professor of Animal Husbandry, Iowa State College, Ames, Iowa 
URING the three or four thous- 
and years in which mules have 
been habitually produced, there 
have been many _ conflicting 
statements of fact and theory in regard 
to the question of possible fertility 
among these animals. Numerous inci- 
dents and cases are on record calcu- 
lated to prove that mules occasionally 
exhibit generative powers. The affirm- 
ative side of the case may be opened by 
the French zoologist André Sanson 
(88), who uncompromisingly maintains 
(Vol. III, p. 145) the occasional fer- 
tility of female mules. He says “‘it 
does not seem inadmissible that the 
males of the same origin as the females 
which show themselves so easily fertile, 
would not themselves behave  simi- 
larly,” and again “if there are fertile 
males, aS we are sure at present that 
there are fertile females . ’ Sanson’s 
claims are unusually broad—most 
writers are more conservative. 
N.S. Shailer (95) comments on the 
‘singular fact that in only two or three 
cases have mules become _ fecund.”’ 
Cossar Ewart (’93) states that mules 
are generally incapable of procreation, 
“though some exceptions to this rule 
have occurred.’ Whitehead (08) in 
discussing the mule makes the paren- 
thetical remark that “‘the cross between 
a female mule and a stallion is known to 
have resulted in offspring.”’ 
Stories accompanied by statements of 
eye-witnesses, of the birth of a foal 
by a mule, and affidavits as to the true 
hybrid nature of the mother, present 
obvious difficulties to those who would 
summarily set aside the whole matter of 
fecund mules as a thing of myth and 
anecdote. At the time of publishing 
the book on Horses, Asses and Mule 
494 
‘ 
Breeding in 1895, Tegetmier was a 
thorough disbeliever in all such cases, 
but in 1897, speaking of fertile mules, 
he mentions a case reported from Mexico 
and says that ‘‘this is one of the most 
detailed accounts of fertility in mules 
that has come under my notice,” and 
urges caution in opinionating. 
PREJUDICE IS STRONG 
Skinner (Youatt, 1854) examined 
very carefully the first-hand evidence in 
regard to the celebrated Norfolk case of 
a breeding female mule and proved to 
his own satisfaction its authenticity. 
He also recognized the deep-seated 
prejudice which people have against 
giving credence to fertility among mules 
for he naively remarks that “‘ Whatever 
doubt may arise hereafter, there is none 
now, of the truth of this case”’ (p. 432.) 
In this case the owner had noticed an 
abdominal enlargement in his female 
mule and had adjusted the shafts and 
harness to accommodate it, “but never 
suspected the mother’s being in foal 
because it was contrary to nature.” 
On April 23, 1834, she unexpectedly 
produced a colt. The mule had pre- 
viously pastured with a 2-year-old 
stallion. Subsequently on August 13, 
1835, the same mule produced another 
colt, a female. Both colts seemed nor- 
mal, but died when afew months old. 
Mr. Gun, an English military veter- 
inarian in India, and apparently a 
faithful and efficient exponent of his 
profession presents (Fvzeld, September 
17, 1898) in elaborate detail the events 
accompanying parturition in an Indian 
transport mule. This is indeed a case 
hard to refute. 
Two cases recently reported have 
come before me and I have been able to 
