130 Mr Heape, Notes on the Proportion of the Sexes in Dogs. 
I am not aware that this has hitherto been done ; the figures 
given are I think not without value and will, I hope, be thought 
worthy of record. 
The Proportion of the Sexes in Dogs. 
Darwin, in his Descent of Man (vol. 1, p. 304, 1871) records 
information he had obtained regarding the proportion of the sexes 
in Greyhounds. From 1857 to 1868, 6878 births were recorded, 
the proportion of males being 1101 per 100 females. 
The figures submitted to him showed very considerable fluctua- 
tion during different years, the extremes being in 1864, when 95'3 
males were produced per 100 females, and in 1867, when the 
proportion of males was 1163. 
Further he states that several great breeders of dogs are 
unanimously of opinion that females are produced in excess. 
Some years ago I collected statistics on this subject and in 
view of the opinion of the breeders above mentioned and of the 
interest now aroused in the sex problem it appears to me advisable 
to record the results obtained. 
The figures Darwin published were those of births of a single 
breed of dogs recorded in the Field. But a dog-breeder does not 
necessarily keep all the offspring produced in a litter, there may 
be more produced than the mother can rear with advantage, in 
which case one or more puppies may be destroyed ; or there may 
be weakly members of the litter which the breeder will certainly 
destroy ; or there may be some puppies born dead. 
Clearly then the proportions he arrived at were not necessarily 
the proportions of the sexes actually borne by dogs of this breed, 
and were certainly not so unless the foregoing sources of error 
were eliminated. 
If it is true, as is suggested, that females are valued less than 
males, in case puppies are destroyed on account of the large size 
of a litter it would be the bitch puppies which would be so 
destroyed, and this custom might account for the opinion that 
females are produced in excess. On the other hand among 
human beings the mortality of young males is greater than that 
of young females ; if the same rule obtains for dogs therefore it is 
to be expected that among weakly members of a litter, which are 
destroyed, males would predominate and Darwin’s figures would 
be below and not above the average for males produced. 
Again the proportion of the sexes in Greyhounds may be 
different from those in other breeds of dogs; there may be a 
racial variation in the proportion of the sexes produced ; and in 
view of the application of Mendelian laws this fact would appear 
to be worthy of attention. 
