A monotonous diet of corn can cause hamsters to become cannibals that eat their young alive.

In a new study, researchers in France wanted to know why the critically endangered European hamster (Cricetus cricetus) saw an alarming drop in population.

Declining Hamster Population

One theory blamed pesticides and industrial ploughing. The hamsters' underground lairs being destroyed is also considered as a possible reason for the drop in population, but these do not appear to be the cause of the rodents' declining numbers.

Mathilde Tissier, from the University of Strasbourg in France, and colleagues decided to take a look into the diet of the hamsters. The researchers wanted to know if diet affected the hamsters' ability to reproduce in the wild.

The animals' diet previously consisted of grains, insects, and roots but the regions where the hamsters' numbers experienced massive decline have been taken over by industrially grown corn.

The change in their habitats also altered the diet of the hamsters. The animals now thrive on a mostly corn diet instead of feeding on a variety of crops, which leave the animals lacking in vitamins particularly vitamin B3, or niacin.

Cannibalism In Hamsters On An All-Corn Diet

In lab experiments, researchers compared the behaviors of the female hamsters that were given varied diets and those whose diet consisted only of corn. They found that four-fifths of the pups that were born of mothers that ate a varied diet weaned. In comparison, only 5 percent of the pups born of mothers who ate only corn reached this stage. The rest of the pups were eaten.

The researchers said that the females stored their pups with their hordes of corn before eating them alive. The hamsters who thrived only on corn were also observed to run in circles in the cage, as well as climb and pound on their feeders. The animals were also observed to have a swollen and dark tongue, hair deficiency, rash problems, and thick blood.

Vitamin B3 Deficiency

It appears that deficiency in niacin is behind the animals' strange behavior. The researchers gave some of the hamsters who fed on a purely corn diet vitamin B3 and noticed that the animals who received additional vitamins began doing normal hamster activities and stopped eating their young.

Researchers said that the consequences of the vitamin B3-deficient corn diet are not due to reduced maternal hormones but because of a change in the nervous system that causes dementia-like behavior.

Tissier and colleagues said that the study sheds light on how nutritional deficiencies that are caused by the cultivation of a single crop such as corn in a given area can affect the reproduction and fitness of farmland animals.

"This study shows that maize-based diets cause high rates of maternal infanticides in the European hamster, a farmland species on the verge of extinction in Western Europe," the researchers wrote in their study, which was published in the British Royal Society journal Proceedings B on Jan. 18.

"Vitamin B3 supplementation is shown to effectively restore reproductive success in maize-fed females."