TIL that monotremes (platypus and echidna) do not simply lay eggs like birds do; the eggs are retained within a mother for some time where they receive nutrients directly from her, similar to pregnancy. This dramatically shortens incubation time compared to reptiles and birds.

https://en.wikipedia.org/wiki/Monotreme
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1o1ccwl/til_that_monotremes_platypus_and_echidna_do_not/