I had always understood that the reason it was done was so that predators couldn’t find the den. I don’t know if it’s the scent of the dead body that they would be attracted to, or just the fact that there would still be something in there all day when the others were out looking for food. That, and it’s probably nutritious.
It’s widely regarded as being common with stressed animals, not so often with happy ones.
In captivity (I work with mice) I’ve noticed that it’s more common with first-time mothers than with second litters. This is purely a WAG, since mothers DO have to eat the placenta and fetal membranes, and lick the babies clean, I wonder if they don’t just get confused sometimes.
On the farm,we raised hogs for a while. After the sows littered,it wasn’t unusual to find half eaten piglets in their pens.This happened to every farmer who raised hogs in the area.It was just part of raising them.Some thought it was a way for the sows to get some sort of nutrition
that they weren’t getting in their regular feed;some thought that mama had too little milk to feed them all,but she could have just killed one or two without eating half their bodies.And I’m not sure about this after all this time,but I remember them always eating the same half.
'Scuse me,I hear mom calling from the house;it’s supper time.I hope we’re having Swiss steak and mashed potatoes and corn scraped off the cob,and strawberry shortcake for dessert!
Boy,this post made me hungry.I can almost see the ghost of Atkins waggling a warning finger at me.
Will attempt an answer from my five years experience of raising the buggers (Campbell’s Dwarf Russians, to be precise).
I’ve never observed the meal itself, just the aftermath. I would imagine it’s the mother who does this, as males tend not to be (overly) involved with the babies.
Difficult to be certain, but likely to be one or a combination of the following: first time mum, disturbed nest, weak/sick offspring.
It’s not common - happened once in my experience of about 20 litters.
Don’t know - keep putting off that field trip to Sino-Russian border!
What’s evolution?!
The birds do it, bees do it, even educated fleas do it.