This happened years ago, so no pictures.
The story: We had a cage with a female gerbil and her babies. There was a coconut shell in the cage with about a fourth of it cut off,and all the the gerbils slept in it. The babies kept growing though. Every night all the gerbils would cram themselves into the coconut,the babies getting bigger and bigger. They all looked healthy,but the coconut was just stuffed full of gerbils. One morning we found that the mother was alive and all the babies except one were dead. later the surviving baby,having grown up,attacked and killed her mother. Why did the babies all die at once? Did anyone out there ever have this kind of problem?