In the Wild, nobody really sleeps the way you all seem to do. If We allow our sensors to shut off completely, We wake up with some strange critter chewing our ankles. Or worse. This is especially true for those of Us that just plop down on the ground at naptime. So although We may appear to be comatose, We are just reinvigorating ourselves for the next round of activity, most likely chewing. And cogitating.
We mostly sleep when We feel like it, both day and night. Sometimes more, sometimes less. Sometimes standing.
Babies sleep soundly, but they are relying on Mom to confront any problems. Moms know how to do that. Moms know everything.