Cannibalism within Millipedes?

[AnnaW]

I have 3 lovely millipedes. They all went in for a molt around the same time. Sandy came out a few days later happy and healthy, but her sisters have been down there for some time. My mom was wondering if she ate them, which would be pretty metal. I'm wondering if they're dead. I haven't noticed any smell but they're under the substrate so idk

 

[Godzilla90fan]

I have 3 lovely millipedes. They all went in for a molt around the same time. Sandy came out a few days later happy and healthy, but her sisters have been down there for some time. My mom was wondering if she ate them, which would be pretty metal. I'm wondering if they're dead. I haven't noticed any smell but they're under the substrate so idk

The millipedes will eat their naturally deceased tank mates, but they will not kill each other. They will pretty much eat anything already dead though.
Some molts take a while. If you are confident they didn't escape, I'd leave them be. If they died, the tank mate will eat the body eventually. If they didn't, you risk hurting them during a molt while searching.

I had a similar situation with my yellow flat backs. Turns out his tank mates scavenged him.

 

[Arthroverts]

Unless you have Spiropoeus fischeri it is highly unlikely that the one cannibalized the other two specimens (and even in the case of S. fischeri cannibalism only happens when specimens molt on the surface from what I hear). Their molt cycles were probably not perfectly timed with the specimen that has already reemerged, or they decided to stay underground, which is not unusual considering millipedes are generally naturally fossorial.

Hope this helps,

Arthroverts