You may hear old country tales that allege moles are all born male and it is not until the following spring that they decide what they need to be, to promote the existence of the species. If the area has an abundance of male moles then some male moles will change into females to ensure a fruitful spring breeding season. - Poppy cock to be truthful or is it?
The myth came from the inability to sex moles, you cannot unless they are in a state of procreation and then the task is a little easier. It is normally accepted that the size could be an indication, with the males in adulthood being larger then a female of a similar age. Nevertheless, you could have two moles of equal length and actually be looking at one of each sex. Unless the females are in an oestrus cycle, it is actually difficult to determine the sex of a mole. When a female comes into her cycle the vagina opens at other times in the year it closes up, hence the statement that all moles are born male and they will decide the following year what it is they wish to be. The male’s penis remains within the body until required – for the future of the moles. This opening and closure of the vagina promotes the success of the moles as it fuels the need for moles to migrate to areas at this important time of the year and prevents genetic disorders with in the species. Therefore, unless the mole is sexually active and the vagina or following the birth of her off spring, the teats can be seen, it is doubtful to be positive of the sex of a mole. In all species, it will be inevitable that some level of inbreeding may occur and some indication for this to have happened in moles could be from some study made over the years. As far back as 1924, study believed that moles might have been hermaphrodites as dissection of moles revealed evidence to such that mixtures of sexual organs were found in some female moles. Further research in the 1990 has continued to find evidence that some female moles had male parts. These parts were the testicular tissue and rudimentary epididymis normally found in males. Personally, I have a theory on this, the marvel of nature being blocked by circumstances out of her direct control. I have mentioned the successful breeding that mole under take every year and the importance of the females not having their oestrus cycles all at the same time. This forces the male moles to move and migrate under the cloak of lust. In areas, where for reasons out of the control of the moles such as man’s intervention or even natural barriers, moles will be confined into areas from which, they have little ability to migrate so will inter relate and inbreeding will certainly result in genetic irregularities. Research into this was carried out in Spain and four species of moles were found to have females that contained additional male reproductive organs. Talpa occidentalis or the Spanish/Iberian mole found in both Spain and Portugal, one of the four species that under went the research was found to have gonads that contain both testicular and ovarian tissue and are referred to as ovotestes and are when both components are present is accepted as a form of Hermaphroditism. The other three species also to have been found with similar components are Talpa Romana from Italy, Talpa Stankovici or the Balkan mole from Greece including the island of Corfu, Albania Montenegro and North Macedonia. The last species was our very own Talpa Europea. I believe this genetic finding is from the pressure of migration requirements not being fully achieved and the cross breeding and it probably has been an occurrence for centuries. We have no evidence recorded in the United Kingdom supporting this claim but as far as I know, there has been no study made despite Great Britain being a small island