Are dwarf hamsters cannibalistic?

One day, many years ago, my young, naive eyes witnessed an event that perplexed young me. I was at a big box store, and naturally, being a young kid, I went to look at the pet section. I was looking at an adorable, dark gray dwarf hamster. I noticed he was chewing on a stick of some sort. Closer examination revealed said stick appeared  to be a (femur or rib?) bone of another hamster. The smokey colored tufts of fur dispersed among the sawdust nesting confirmed my assumption: that the hamster ate his roommate. Do hamsters really eat/kill each other, or did my eyes deceive me or was that just an unnaturally crazy hamster?