In the wild, many animals give birth to their offspring in the spring when mating season starts and most females are in search of a mate. This makes perfectly sense, as Mother Nature seems to have well orchestrated the events so that juveniles are granted more chances of survival once the rigors of the winter are over and there are more sources of food around. But what about dogs? Has domestication changed anything, considered that now pets live in homes and are well-cared for from their humans?
Call of the Wild
In the wild, wolves are seasonal breeders, meaning that they breed only at certain times of the year. To be precise actually, wolves go in heat only once a year and mostly in the spring when their offspring have higher chances for survival.
During the months when female months are not in heat, a male wolf's sexual organs actually sort of go into a "dormant state" shrinking in size.
According to Steven Lindsay, when it's not breeding season, the male wolf's testes atrophy, which technically means that they become infertile.
A Matter of Domestication
And what about our domesticated companions? It seems like domestication must play a role in the way dogs reproduce nowadays. Gone are the days when mother dog had to build a den to protect their off spring and the pups totally depended on her for survival.
And gone are the days when mother dogs had to eat an abundance of meat and then rush to their dens to regurgitate for their pups when weaning them off of her milk.
Today, mother dogs whelp in whelping boxes, weak puppies are bottle fed and puppies are fed mush from the breeders when they are in the process of being weaned. Along with these changes associated with domestication, is the fact that dogs go in heat at any time of the year and they are fertile any time too!
What Studies Say
Interestingly, some studies have been conducted on the periods of receptivity in female dogs of different breeds and crossbred dogs.
According to these studies, a female dog's estrus activity remained the same whether it was January or July. Only a slight reduction in the activity was noticed in December, while the remaining months remained basically similar.
Seasonality of estrus cycles therefore mostly remain a thing of the past and are mostly seen in feral dog populations. Quite fascinating how this species evolved, no?