Are Any Animals Born Pregnant?

The aphid, a type of insect that lives off the sap of plants, is born pregnant. Aphids reproduce parthenogenetically, meaning that there is no need for sexual contact. Instead, aphids are born with viable eggs in their bodies, and they give birth to live nymphs. Aphids typically start giving birth after having lived 10-14 days.

More about unusual reproduction:

• There is evidence that naked mole rats produce male or female sperm in response to a colony's need for one sex over the other.


• Unlike most other animals, male seahorses become pregnant. They carry their fetuses in brooding pouches.


• Fetus in fetu is a condition in which an animal, human or non-human, absorbs the body of a twin while still in the mother's uterus. These cases are very rare, although one is occasionally discovered when a person has surgery to remove a lump or tumor and doctors realize that the mass is actually an undeveloped fetus.

Frequently Asked Questions

Are any animals born already pregnant?

Yes, some animals are indeed born pregnant, a phenomenon known as paedogenesis. Aphids, for instance, can have embryos developing inside them when they are born. This reproductive strategy allows for rapid population growth and can be advantageous in environments where conditions change quickly or resources are abundant.

How does paedogenesis work in the animal kingdom?

Paedogenesis is a form of asexual reproduction where the offspring are produced by an immature juvenile. In some species like aphids, the young are clones of the mother, and females can give birth to live young without mating. This process can lead to several generations being born in a single season, greatly increasing population numbers.

What is the advantage of being born pregnant for these animals?

Being born pregnant allows certain species to maximize their reproductive output and take advantage of favorable environmental conditions. It eliminates the need for finding a mate, which can be energy-consuming and risky. This reproductive strategy can quickly establish a strong presence in a new habitat or after a seasonal die-off.

Can any vertebrate animals be born pregnant?

No known vertebrate animals are born pregnant. Paedogenesis is primarily observed in invertebrates, such as some insects and mites. Vertebrates typically have more complex developmental stages and reproductive systems that do not support this type of reproduction. Their life cycles usually involve mating and a gestation period before offspring are born.

Is paedogenesis common in the animal world?

Paedogenesis is relatively rare in the animal kingdom. It is an unusual reproductive strategy that is only advantageous under certain ecological conditions. Most animals reproduce sexually and go through a typical life cycle of maturation before they are capable of producing offspring. Paedogenesis is mostly observed in certain insects and mites.

Does paedogenesis affect the genetic diversity of a species?

Yes, paedogenesis can affect genetic diversity since it often involves asexual reproduction, leading to offspring that are genetically identical to the parent. This can make a population more susceptible to diseases and environmental changes, as there is less genetic variation to allow for adaptation. However, some species employing this strategy can also reproduce sexually when conditions favor genetic diversity.