How long does a platypus stay pregnant?

Answer 1

Although platypuses are mammals, they do not actually have a "pregnancy", as they are egg-laying mammals.

Limited rematch has been able to be done on the platypus, but fertilised eggs are believed to stay in the mother's body for around 28 days before being laid. The eggs are incubated by the mother in the nesting chamber for another 10 days. During this time, she does not eat or drink.