Abandoned and feral cats rarely have regular sources of food.  They must scavenge whatever sources of food they find - dustbins, handouts, and dead bodies (including their own species).  desperate ferals have been seen eating soiled nappies and sanitary napkins as well as bread, fruit and vegetables that cats cannot digest.  Some have resorted to eating earth just to relieve their hunger.  Post mortems of feral cats have found some to have stomachs full of insects.

Bodies of larger animals pose problems as the domestic cat's jaws are designed for small prey, hence they are most likely to tackle the extremities such as fingers and toes.  Although cats normally avoid decomposing flesh to avoid food poisoning, cats with no other options will try to eat a dead body that has begun to rot and soften.

Like other scavengers, those cats are doing a clean-up job.  without scavengers, we would be knee-deep in rotting flesh.  Even when bodies are decently buried, they are being invisibly consumed.