Some humans may sometimes envy cats. Consider the women who, according to a video Billy Hallowell discusses, are concerned that their fetuses may self-abort during the days before the women have scheduled surgical abortions...
"If it moves..." Ask my cat Heather. Possibly in order to induce lactation and adopt her orphaned brother, Heather gave birth to some, not all, of her kittens a week ahead of the others. If she did this as anything like a human's "effort" or "experiment," it failed; only one of Heather's premature kittens moved around on its own. And neither it nor its uncle was alive by the time the normal-looking kittens came out into the world. However, there was no doubt in Heather's mind that her Preemie was alive and deserved to be fed, cared for, and generally given as good a life as possible during the short time it was here.
Some humans should have as much common sense as some cats.