[anonymous]

Food aggression in dogs
Dogs with food aggression may stiffen their body, show teeth, growl, snap, or bite when they are approached by a person or another animal when they are in possession of or near a food-related item such as a rawhide chew, bone, pig’s ear, food bowl, sandwich wrapper, or food that was dropped on the floor.
Reference: centerforshelterdogs.com/home/dogbehavior/problemsandmanagement/f…

Here is another article https://www.aspca.org/pet-care/dog-care/common-dog-behavior-issues/food-guarding excerpt below
Guarding possessions from humans or other animals is normal behavior for dogs. Wild animals who successfully protect their valuable resources—such as food, mates and living areas—are more likely to survive in the wild than those who don’t. However, we find the tendency to guard valued items undesirable in our domestic pets, especially when the behavior is directed toward people.
Resource guarding in dogs can range from relatively benign behavior, like running away with a coveted item or growling at an approaching person, to full-blown aggression, such as biting or chasing a person away. Some dogs only direct resource guarding toward certain people, often strangers. Other dogs guard their resources from all people. Dogs vary in what they consider valuable. Some dogs only guard chew bones or toys. Some guard stolen items, such as food wrappers from the trash can or socks. Many dogs guard food.