Animals and insects that eat dead animals have been studied in the context of forensic matters and ordinary biological curiosity. There is a far from simple relationship between which species that eat carrion, what they eat, and the order in which they appear and also any external circumstances. Some natural scavengers may act as food pests.
1. Pests in damp carrion:
Wasps seek out dead animals to provide feed for their larvae. Maggots live in fresh carrion in the wild, but also place eggs in our meat, which of course, strictly speaking, also is fresh carrion. Cheese skippers often eat moist cheese as a substitute for carrion. It also applies to blowflies, that both cheese and droppings can be eaten instead of carrion. Milk, which is a thin suspension of animal fat and protein, can attract common houseflies and blowflies, when it becomes sour and cheesy, and their larvae can develop in milk residues. Open wounds and infections – also in humans – can tempt blowflies to lay eggs. Pharaoh ants collect meat and can go into wounds.
2. Pests in dry carrion:
Skin beetles (not the khapra beetle) copra beetles, spider beetles and various moth larvae play a major role in the final digestion of animal tissue. Other pests can participate in the feast as animal protein is an attractive food, even for pests that would otherwise be vegetarians. Milled products of animal origin (meat meal, bone meal, dried blood, dried milk, egg powder, cheese powder etc.) also get infested by the scavengers who prefer dry carrion. It is often overlooked that these things are used in many other products which is not immediately reminiscent of dry carrion. This is among other things compound feed for animals, certain fertilizers and dried soups. Animal fat in its pure form (such as butter) or artificial plant fats (such as margarine) is not attractive to insects and mites, but mice, rats and birds like these things.