Evolution question - mother animals squashing their babies?

I spent the weekend with my friend and her dogs, one of whom has eight new puppies. She told me how (reasonably) common it is for mom dogs to accidentally crush their pups by sitting/stepping/rolling over on them.

Someone mentioned something similar about farm animals in the current ear-snipping Pit thread.

It would seem to me that there would be very strong and direct evolutionary pressure against this - any animal that didn’t squish their babies would have more surviving offspring than those that did, right? Any mutant gene that reduced or prevented puppy-squishing would surely come to prevail in the population. Right?

What’s up with this?

I have no answers for you, but your question reminded me of Sally, a beagle my father had when I was a kid.

Sally was a hunting dog, bought as a mate for Sport, our other hunting beagle. Between the two of them they had the brainpower of a gnat.

Sally got pregnant easy enough, had about 6 pups if I recall correctly. She managed to smother 5 of them. When it appeared the final pup would survive, my Dad decided it was time to name him. He didn’t think too long before he came up with the name “Lucky.”

It happens to human babies as well. Parents are routinely warned to never sleep with an infant, but some do. Some of those parents wake up with dead babies.

Cite, please? Having slept with my children when they were very young, I find it hard to believe that you could kill them that way. You are much too aware that they are there, even when asleep.

If anything, the adaptation would be for a puppy to become more aware, or in some manner to learn to avoid this potential danger, than for a mother to develop an adaptation to avoid smothering her young.
Evolution tends to follow more of a rule of “surviving until able to pro-create”, not so much “ensuring that all the offspring survive”. That is, it is more of a priority to get an individual to the point of being to bear offspring, than for all those offspring to make it.
There are many examples where very few, and sometimes only one, offspring is “allowed” to survive - by very deliberate actions taken by the parents. I can think of a number of examples in the bird world, for instance.
So the rule in nature tends to favor “quality” over “quantity”.




Conversely, at the fair this year, I saw a huge mother pig that was in a pen that was barely big enough for her and she had like 15 piglets that were 6 days old. I saw her stand up, turn around and lay back down and marveled that she didn’t step on a single piglet or lay down on one.

My mother told me she almost smothered me while still in the hospital when I was born. The nurse brought me to Mom to feed, and she went back to sleep.

Your second cite suggests that it may be safer for babies to sleep with their parents than to sleep in a crib (even if it does offer some precautions).

HBO has a series called Autopsy with Dr. Baden. In one of those episodes he declared that a mother accidently smoothered her baby when sleeping with it. http://www.hbo.com/autopsy/

It seems that humans only accidentally smother their offspring when sleeping, while animals (at least the one I saw) would do it through careless sitting or placing of feet. Are there many cases of human mothers accidentally doing it while awake?

I thought evolution was exactly about producing offspring that could survive long enough to produce surviving offspring, but your interpretation seems more consistent with the fact of puppy-squishing.

Well, it’s different because humans usually only have one at a time. Makes it a little easier to keep track of. If I had a litter of 10 children, I might “accidentally” sit or step on one. :wink:

From last week’s Los Angeles Times: Newborn Suffocates Between Sleeping Parents

Also animal babies are more mobile, any many animals have more of a blind spot when lying down. And I suppose puppies and piglets, coming in large batches, are smaller in comparison with their parents, than the average human baby.

How could this possibly work? You can’t select against accidents. There are no “non accidental puppy squishing” genes, any more than there are non “getting hit by a falling tree in the forest during a storm” genes. Accidents happen. It sucks. “Nature red, in tooth and claw…” and all that. But that’s why many animals have multiple offspring in the first place: because not all of them are likely to make it, for whatever reason.