Uncovering the secrets of animal menstruation: Which animals have menstruation? What impact does it

Menstruation is a common phenomenon in human females during their reproductive cycle, but not all animals experience this process. In fact, menstruation is a relatively rare phenomenon in the animal kingdom, and only a few species experience physiological cycles similar to humans. This article will reveal which animals have menstruation, the impact of menstruation on animal health, and its significance in biological evolution.

1. What is menstruation?

Menstruation refers to the phenomenon that the endometrium in female mammals falls off and is discharged through the vagina as the reproductive cycle changes. During the menstrual cycle, if there is no fertilization, the hormone level in the body decreases, causing the endometrium to fall off and be discharged from the body. The cyclical process of menstruation is closely related to the operation of the reproductive system.

In human females, menstruation occurs about every 28 days, and this physiological phenomenon is closely related to the preparation and repair process of the reproductive system.

2. Which animals have menstruation?

Although many mammals have reproductive cycles, only a very few animal species experience menstruation similar to humans. These animals are usually primates.

a. Primates

Menstruation is relatively common in primates, especially chimpanzees, bonobos, baboons, and apes. Similar to human females, these animals also experience cyclical menstruation. The menstrual cycle of primates usually lasts about 30 days, similar to humans.

b. Some bat species

Certain species of bats, such as fruit bats, also experience a process similar to menstruation. Scientists believe this is because their reproductive mechanisms are similar to those of primates, especially in terms of ovulation and changes in the endometrium.

c. Elephants

Elephants have also been found to have a reproductive cycle similar to menstruation. Although elephants do not have obvious menstrual discharge, their endometrium also undergoes changes in thickness and partial shedding during the reproductive cycle.

3. Reproductive cycle of most animals: estrus

Although humans and some animals experience menstruation, most mammals do not have such a physiological process. Instead, many animals use estrus cycles to regulate reproductive behavior.

Estrus is a stage in the reproductive cycle of female animals when they are more receptive to mating. Unlike menstruation, the endometrium of animals in estrus is not shed and expelled from the body like humans, but is reabsorbed. Therefore, most mammals do not have obvious bleeding.

4. Evolutionary significance of menstruation

Why do only a few animals experience menstruation? This question has puzzled scientists for many years. There are several hypotheses to explain the evolutionary significance of menstruation.

a. Protection of reproductive health

Menstruation may be a protective mechanism to prevent infection by pathogens in the endometrium. During the menstrual cycle, the endometrium is shed and expelled, which may help to remove potential pathogens and thus protect the health of the reproductive system.

b. Reproductive regulation

Menstruation may be related to the mother's selection of embryo quality. During evolution, the periodic renewal of the endometrium ensures that only the healthiest embryos can successfully implant and develop. This screening mechanism helps to improve the survival rate of offspring.

c. Optimization of energy consumption

Menstruation may be an optimization of resource consumption by organisms. The periodic shedding of the endometrium can reduce the body's maintenance and repair of unnecessary tissues, help save energy, and thus provide more resources for other physiological activities.

5. The impact of menstruation on animal health

Like humans, animals that experience menstruation may also face related health problems. Bleeding, pain, and hormonal fluctuations caused by menstruation can affect their behavior and physical condition. For example, primates may show symptoms such as more fatigue and reduced activity during menstruation. In addition, long-term imbalance in the reproductive cycle may also have adverse effects on the reproductive capacity of animals.

In zoos or laboratories, researchers often closely monitor the reproductive health of these animals to ensure that they are in good condition during their menstrual cycles.

6. Differences between menstruation and human women

Although some animals have similar menstrual phenomena to human women, they differ in terms of cycle length, menstrual blood volume, and duration of bleeding. For example, chimpanzees have longer menstrual cycles than humans, while some bats have relatively less menstrual bleeding. These differences reflect the diversity of reproductive physiology among different species.

7. Conclusion: Biological and evolutionary significance of menstruation

Although menstruation is relatively rare in the animal kingdom, its existence reflects the complexity of the evolution of the reproductive system. The menstruation of primates, some bats, and elephants provides important clues for our understanding of reproductive health, evolutionary biology, and reproductive mechanisms. Future research may further reveal the role of menstruation in different animal species and explain its profound impact on animal health and evolution.

Animal menstrual cycle

In the animal kingdom, menstrual cycles similar to those of humans are very rare, and only a very few species experience a complete menstrual cycle. The following are several known animals with menstruation and their approximate menstrual cycles:

1. Humans

• Menstrual cycle: average about 28 days (can be between 21-35 days).

• Menstrual duration: 3-7 days.

2. Chimpanzees

• Menstrual cycle: about 28-35 days.

• Menstrual duration: 3-6 days. The menstrual cycle of chimpanzees is similar to that of humans, with bleeding and shedding of the endometrium.

3. Bonobos

• Menstrual cycle: about 32-35 days.

• Menstrual duration: 3-5 days. Bonobos have slightly longer menstrual cycles than chimpanzees, but the bleeding duration is similar.

4. Baboons

• Menstrual cycle: about 30-35 days.

• Menstrual duration: 2-4 days. Baboons also have similar menstrual cycles, but their menstrual duration is shorter.

5. Apes (such as gorillas)

• Menstrual cycle: about 28-30 days.

• Menstrual duration: 3-5 days. Apes have similar menstrual cycles to humans.

6. Fruit bats

• Menstrual cycle: approximately 28 days.

• Menstrual duration: 1-2 days. Fruit bats are one of the few non-primates known to experience menstruation, and although their bleeding is small, their cycles are relatively stable.

7. Elephants

• Menstrual cycle: about 16 weeks (4 months). Elephants do not experience obvious menstrual bleeding like primates, but their reproductive cycle is relatively long, manifested by cyclical changes in the endometrium.

8. Other primates

Some other primates, such as ring-tailed lemurs and gibbons, may have similar cycles, but due to less research, the specific menstrual cycle data is not yet fully determined. Generally speaking, the cycle length of these primates is similar to that of humans and other primates, usually between 28-40 days.

Conclusion

Menstruation is quite rare in the animal kingdom, mainly occurring in primates and a few other species. Most mammals use an estrus cycle rather than a menstrual cycle. Although the menstrual cycles of these animals vary in length, they usually have some similarities to the human reproductive cycle.

When do animals menopause?

Menopause is the phenomenon in which an organism stops having reproductive functions, ovulation, and menstruation. Unlike humans, most animals do not go through a menopause-like stage. Most animals remain reproductive in the last stages of their lives, and only a few species experience true menopause. The following are several animals known to experience menopause and their approximate time of menopause.

1. Human

• Age of menopause: Usually between 45 and 55 years old.

• Life span and menopause: Menopause in human women usually occurs in the middle and late stages of life, and they can stillLive for many years (usually 20-30 years).

2. Orca (Killer Whale)

• Menopause: Around 35-45 years old.

• Lifespan and Menopause: Orcas can survive for decades after menopause, with an average lifespan of 50-80 years. Older female orcas will play the role of "family leader" after menopause, helping to protect and guide the group.

3. Short-finned pilot whale

• Menopause: About 30-40 years old.

• Life span and menopause: After menopause, they can still live to about 60 years old. After menopause, females continue to play an important role in the group, especially in protecting and caring for offspring.

4. African elephant

• Menopause: Although African elephants do not have true menopause, the reproductive capacity of female elephants will decline significantly around 40-50 years old.

• Lifespan and menopause: African elephants usually live up to 60-70 years, and female elephants still play an important role in socializing and raising children in their later years.

5. Other primates besides humans

Most primates, such as chimpanzees, bonobos, and baboons, experience a decline in fertility, but do not have a clear menopause stage like humans. Female primates usually retain some reproductive capacity in the last stages of their lives and do not completely stop ovulating.

6. Other animals

Most mammals do not experience menopause, and they continue to ovulate and reproduce until the end of their lives. For example, common mammals such as dogs, cats, and horses, although their fertility declines as they age, do not experience obvious menopause like humans do.

Why do only a few animals experience menopause?

Scientists have proposed many theories as to why some species experience menopause. One of the most famous hypotheses is the grandmother hypothesis, which states that in some social animals, older females stop giving birth, which helps them focus on caring for their existing offspring and grandchildren, thereby improving the overall survival rate of the group. This phenomenon is particularly evident in killer whales and humans, where older females can help the group cope with challenges through their experience and wisdom.

Conclusion

Although menopause is common in humans, it is extremely rare in the animal kingdom. In addition to humans, only a few animals such as killer whales and short-finned pilot whales experience menopause. These species survive for many years after menopause, continuing to provide important social and parenting support to the colony.

animal tags： Menstrual.phenomenon