From feasting on human flesh to their starring roles in our most beloved B-movies, zombies have been an integral part of American life for generations. But now, experts believe that our favorite undead abominations may be in jeopardy. According to a recent study, the zombie species’ precarious position on the food chain puts it in danger of extinction.

The theory comes out of the interrelation between population and food supply. In addition to their slow speed, one of the most debilitating characteristics of zombies, according to ecologists, is their reliance on a single food source—human brains. Typically, this means that the zombie population rises and falls in proportion to the human population. A rise in the human population produces more food for zombies, which means that the zombie population will also grow. This will continue until there are too many zombies for the human population to support, at which time the zombie population will decrease, and the human population will begin to rise again. Thus, the two species exist in a sort of equilibrium. This relationship can be seen in the chart below.

However, unlike their homo sapien prey which will eat practically anything, zombies will not eat anything other than this single food. Due to this lack of diversification in their diets, any unexpected change in the human population could have potentially disastrous results for the species. This has some zombie rights advocates concerned, given the volatile nature of the human population.

According to a spokesperson for the Zombie Preservation Society (ZPS), “With all of the threats facing humanity, from nuclear weapons, to global warming, to overpopulation, zombies’ singular reliance on human brains for food could very well prove to be their undoing.”

There may yet be hope for these hellish creatures, though. Zombie expert Dr. George Andrew believes that the zombie’s concept of food is largely socially constructed and that zombies can be taught to take advantage of other sources of food. Said Andrew, “We know that zombies are physiologically capable of eating a wider variety of food than just humans. For instance, chimpanzee brains and gorilla brains have been shown to be at least as suitable for the nutritional needs of the zombie body as human brains.” Andrew is currently working to learn what foods zombies are capable of eating and hopes to help the failing species by introducing this wider variety into the zombie population.

Meanwhile, zombie lovers everywhere continue to hope and pray that their favorite undead monster does not go the way of the dinosaur mummy.