This Animal Can Postpone Its Pregnancy
Roe deer can, incredibly, postpone their pregnancies. Could humans benefit from a similar superpower?
In the wild, animals are always battling to find their next meal and avoid being eaten by predators. The key to survival is to be the fittest of all. Over millions of years, animals have developed astounding competencies that assist them in surviving in their surroundings.
Some of these unique capabilities may seem like superpowers to humans. The abilities of animals to produce electric shocks to stun prey, alter colour or pattern to blend in with their environment, use echolocation to travel and find food, and many other such abilities have frequently fascinated men. Humans have been able to make remarkable discoveries inspired by the abilities of animals. Though we understand and mimic some of them through technology, many are still a mystery to us, and the full extent of their capabilities is yet to be discovered.
The roe deer (Capreolus capreolus), a species of deer, has a unique way of surviving through embryonic diapause. They are small, reddish-brown deer 🦌 that have evolved special cold-weather survival skills. They are distributed throughout much of Europe, from the Mediterranean to Scandinavia, from Scotland to the Caucasus, and farther east to northern Iran and Iraq.
According to an official journal of the Society for Reproduction and Fertility, embryonic diapause, also known as discontinuous development or, in mammals, delayed implantation, is among the evolutionary strategies that ensure successful reproduction. It comprises the uncoupling of mating and fertilisation from birth and serves to maintain the developmental arrest of the embryo, usually to ensure that postnatal development can be completed under more favourable environmental conditions.
Here is a research paper to learn more about the phenomenon.
When a female deer mates, she has the ability to postpone the development of the embryo. She can put this development on hold. If she faces a tough winter in the coming months, she may decide to terminate the pregnancy to avoid draining her precious resources. However, if she can find enough to eat and is in good shape, she can begin her pregnancy in the late winter and be ready to give birth in the spring. This is a strategy to ensure that the female gives birth when she is healthy enough to nurture a newborn.
As the only known species among the artiodactylae, the roe deer displays a long period of embryonic diapause. The preimplantation blastocyst reaches a diameter of 1 mm only at around 4 months compared to around 13 days post estrus in cattle. The expanded blastocyst survives in a uterine microenvironment that contains a unique set of yet unidentified factors that allow embryonic stem cells to proliferate at low pace without impairing their developmental potential.
Other mammal species can also postpone pregnancy through embryonic diapause. Some examples include black bears, raccoons, muskrats, some species of bats, caribou, and moose. William Harvey (1578–1657) made the first known observation of menopause while accompanying King Charles I on roe deer hunts. After examining the uterine contents, he observed differential states of embryonic development (Hunter, 1995).
What if humans had this superpower?
When I first learned that animals can delay pregnancy, I was quite fascinated. This set me to pondering: Would humans benefit if they could do the same? There may be some benefits to society from gaining this superpower.
Animals benefit from this reproductive strategy in situations that seem unfit to raise offspring. In the case of humans, factors that could seem unfavourable for giving birth include financial strain, psychological stress, societal pressure, and persistent health concerns of the female both before and during pregnancy.
How can embryonic diapause benefit humans?
Reduction of unintended pregnancies
Unwanted pregnancies are one of the most worrying public health issues globally, placing a significant socioeconomic burden on individuals and society. Women having control over when to get pregnant could possibly reduce the number of unintended pregnancies. Some reasons for unintended pregnancy include lack of access to birth control, lack of knowledge about birth control methods, and religious or cultural beliefs that discourage the use of birth control. Controlling an unintended pregnancy can eliminate the financial strain on the woman and her family, which affects the woman’s ability to work or continue her education.
Avoiding the risks associated with closely spaced pregnancies.
There are multiple risks to spacing pregnancies too closely. Some of these include premature birth, placental abruption, low birth weight, and maternal anaemia. Embryonic diapause could help to improve maternal and child health, as women could space out their pregnancies more effectively.
To reduce the risk of pregnancy complications and other health problems, women should wait 18 to 24 months but less than five years after a live birth before attempting their next pregnancy. “Waiting 18 months before you get pregnant again allows time for your body to heal and reduces your risk of pregnancy complications,” says Erin Clark, MD, an OB/GYN at the University of Utah Health.
However, this reproductive strategy may pose some difficulties for humans. If the woman delays the pregnancy for a long time, the age of the mother increases, which could increase the risk of complications for both the mother and the baby. Risks associated with advanced parental age include infertility, miscarriage, birth defects, poor neurodevelopmental outcomes, and childhood cancer. Read this reference for more information on the impact of paternal ageing on poor reproductive outcomes.
While the ability to delay implantation could have some advantages for humans, it’s hard to say if it would be overall beneficial or detrimental without taking into account the complexity of human societies and the challenges that come with it. The ability of delayed implantation in roe deer and other animals has evolved to help them survive in challenging environments, but human society and technology have advanced in a way that may not make it as necessary for humans as it is for wild animals.
Please note that the above points clearly reflect my limited knowledge of medical science.
