Elephant can be pregnant for upto 2 years

A team of researchers working out of research centers in Canada and Germany have finally solved the mystery. As they write in their paper published in the Proceedings of the Royal Society B: Biological Sciences, elephants are able to carry their young so long because they create more of the temporary glands that monitor hormone levels during ovulation and pregnancy.

In order to reproduce, female mammals have ovaries that produce eggs that when fertilized by sperm grow into babies. In humans, in addition to producing an egg, inside of each ovary, a gland called the corpus luteum develops during ovulation that helps to regulate hormone levels by generating progesterone. If the egg is fertilized, the gland continues to help monitor hormone levels to keep things in the uterus as they need to be to allow a baby to develop. If the egg is not fertilized, the gland shrivels and disappears, paving the way for a new one to emerge the next time an egg is produced in the ovary. All of this allows humans to carry a baby for the typical nine months needed before delivery.

In elephants, it turns out, things are quite a bit different. Instead of creating just one corpus luteum they create on average five. Like humans, one of the glands is formed by the same follicle in the ovary that generates the egg during each menstrual cycle. Unlike humans, however, the other glands are created by other follicles in the ovary, though they all appear to serve the same basic service, namely, stabilizing the hormonal environment to ensure the successful conception and then carrying of a baby. But what’s really interesting is that the glands don’t all form at the same time, they arise over time. As one gland begins to slow its production of progesterone, another is created to take its place, and this is how the elephant manages to keep a baby going inside of it for so long.