I have experienced the death of one sister gerbil in the case of two sister's/cage mates. Believe it or not the living gerbil will actually burie the other and continue on living as if she's not there. Unless the gerbils are starving they wont eat the dead cage mate.
Yes they will
It is likely your gerbil died of natural causes and the other one was just disposing of its body. It is not very nice to think on but makes a lot of sense in the wild as a dead body would just attract predators.
Yes, it is strange but true, gerbils will eat other gerbils.
Yes, it is possible and likely that the cat would try to catch, kill and maybe eat the gerbil. You should keep the gerbil in a cage that isn't accessible by the cat.
it depends on the cat
Gerbil food.
feed it. But seriously, if the gerbil refuses to eat, perhaps try different gerbil-firendly foods. And if all else fails, see a vet. If the gerbil will not eat, you may want to see a veterinarian. The gerbil might have a tooth that is bothering him.
No
with a side of gerbil
No! They will be scared of each other and the parrot might try to eat the gerbil.
If it is stale then yes.
Noooooooo!!!