A new study suggests that filial cannibalism is linked with parental care. The act is common among some animal groups, such as mammals and birds.

According to researchers, both filial cannibalism and offspring abandonment can coincide with other conventional forms of parental care such as feeding, guarding, and grooming.

Tough Love

Several factors for offspring survival is one of the reasons for filial cannibalism to occur. Researchers from the University of Oxford and the University of Tennessee have made a mathematical model to prove this theory.

The results show that in some cases when overcrowding becomes a threat for offspring survival, some parents sacrifice a few of their young so that some of their offspring can survive.

The findings of the study was published in the journal Frontiers in Ecology and Evolution.

Survival Benefit

The researchers focused on the animal groups that lay eggs in order to further understand the survival benefit of filial cannibals and the role of offspring density.

"Communal egg laying is common in a range of fish, insects, reptiles, and amphibians," said senior author of the study Dr. Hope Klug, associate professor at the University of Tennessee, Chattanooga.

"This makes it easier to protect, clean, incubate and feed the eggs-but can also increase disease transmission, and competition for food and oxygen."

Researchers have found that filial cannibalism is a major form of survival adaptation in density-dependent animals such as the beaugregory damselfish, where fathers often eat their own eggs under low-oxygen conditions.

Increased Fitness

In the mathematical model, Klug and his colleagues put an imaginary individual with a mutation for offspring abandonment and filial cannibalism into a group of generic egg-laying animals.

They found that increased fitness is the result of offspring abandonment and filial cannibalism when offspring mortality increases with egg laying density. The model shows that the mutants were able to replace and outcompete the generic population.

Prof. Michael Bonsall of the University of Oxford, co-author of the study, said that whenever the adult death rate increases, the fitness benefit of filial cannibalism and offspring abandonment also increases.

Scientists were perplexed by this phenomenon because why do they lay so many eggs in the first place when mortality is density dependent?

According to Bonsall, there are many unpredictable factors for this to happen such as disease presence, oxygen availability, food availability, and predation. The researchers think it's up to the empiricists to test these models in a variety of species.