Why is it that dogs always produce several puppies whereas humans produce only one child at a time?
Dog releases many eggs at a time and they are fertilized by sperms which produces multiple puppies. Also Survival rate of puppies are very low, so to maintain the survival of species they produce many puppies at a time. Whereas in case of human only one ovum is fertilized by sperm which results in one baby. Sometimes human also can give birth to more than one baby.