Penguins of the little, Adelie, yellow-eyed and Magellanic varieties catch jellyfish in the sea, caught on cameras mounted on their backs and the backs of other penguins (Provided by the National Institute of Polar Research)

Penguins regularly feast on jellyfish, a species that had been considered an unlikely choice due to its low nutritional value, Japanese scholars discovered.

Researchers from the National Institute of Polar Research mounted tiny video cameras on the backs of certain kinds of penguins to ascertain what they hunt at sea.

“This finding means we may need to reconsider the role of jellyfish in the food chain of marine creatures,” said Akinori Takahashi, an associate professor of animal ecology at the institute.

Jellyfish literally have jelly-like bodies, and 95 percent of their body mass is water. As they are almost devoid of nutrients, it had been believed jellyfish would not be part of the diet of any larger marine creature that requires a lot of energy to maintain body temperature.

The team attached small video cameras on the backs of 106 of penguins of four varieties inhabiting seven locations in Antarctica, Australia, Argentina and New Zealand from 2012 to 2016 to learn what they eat.

The result revealed that most of the four species usually feed on small fish, but, on average, 42 percent of the little penguin’s diet is jellyfish. The Adelie and Magellanic penguin varieties, on the other hand, made up 4 to 5 percent of their diets with jellyfish.

According to Takahashi, the penguins gulp down smaller jellyfish whole, and if they are too big, they munch off parts containing more nutrients than others.

“It seems they eat them not because there is no other food available,” said Takahashi.

A paper on the findings was published in the U.S. journal Frontiers in Ecology and the Environment in September.