What Happened to the Rabbit’s Ear Tips?

I’ve seen a lot of Cottontail rabbits with the tips of their ears missing and wondered what cause that.  Are predators trying to snatch the rabbits and rip their ears instead?  Are the rabbits chewing on them because they’re mite-ridden or something?  Is it a kind of birth defect?

All of them are possibilities, but I found one source that suggested that the damage is usually caused by the rabbits’ mother when they’re newborns.  Mother rabbits enthusiastically eat away the placenta and umbilical cord, and clean off their bunnies when they’re born.  Sometimes, the mother gets carried away or misses the mark and inadvertently chews off the bunnies’ ear tips.  Some moms are even known to chew of the bunnies’ tales or feet!

“… Thankfully, only in a very small minority of such cases does this result in the death of the baby due to vital parts of the body being eaten as well.  Most of these accidentally mutilated baby rabbits grow up to lead normal lives…”