General Knowledge
How long is a kangaroo pregnant for?
- About a month
- About six months
- About a year
The answer is About a month. Roughly 33 days - the rest of it happens in the pouch.
About 33 days, which is remarkably short for an animal that size - a red kangaroo is two metres tall and gestates for roughly the time a rat does. The newborn is about two centimetres long, blind, and essentially an embryo with forelimbs, and it crawls unaided up through its mother's fur to the pouch, where it attaches to a teat that swells inside its mouth to hold it in place.
Marsupials have moved most of development outside the body, and the machinery that comes with it is extraordinary. A female can simultaneously have a joey at foot, a second in the pouch, and a fertilised embryo held in suspension waiting for the pouch to clear - and can produce two different milks at once from adjacent teats, one formulated for a newborn and one for an older sibling.
The suspended embryo is a drought strategy. In poor conditions development simply pauses, indefinitely, and resumes when the rain comes - so a kangaroo population can respond to a good season far faster than any animal locked into a fixed gestation could. In hard years, a female will also abandon the pouch young to save herself, which reads as brutal and is the arithmetic of a place where the rain is not reliable.