 Contrary to previous research, the echidna does enter REM sleep, but only when the ambient temperature is around 25 °C (77 °F).At temperatures of 15 °C (59 °F) and 28 °C (82 °F), REM sleep is suppressed.The female lays a single soft-shelled, leathery egg 22 days after mating, and deposits it directly into her pouch.