Britannica Sources used in this answer

What is embryonic diapause in kangaroos?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Red kangaroos on the move — kangaroo A group of red kangaroos (*Macropus rufus*) using their powerful hind legs and feet to hop.

Embryonic diapause is a reproductive strategy found in many marsupial species, such as kangaroos, that allows them to pause the development of an embryo.1

After a female mates and conceives while a previous joey is still in the marsupium, the newly formed embryo develops for about one week before entering a state of suspended animation known as diapause. This dormant state persists until the older joey begins to leave the pouch or environmental conditions become favorable. Once the pouch is vacated, the embryo’s development resumes, leading to birth after a gestation period of approximately 30 days.1

This mechanism is considered an evolutionary adaptation that enables populations to recover quickly following periods of drought, during which breeding typically ceases and diapause is prolonged. Notably, this system is absent in gray kangaroos, which inhabit more predictable environments.1