Japanese scientists have captured a rare video footage of Adelie penguins' feeding habits.
Researchers strapped small video cameras and accelerometers to the back of Adelie penguins (Pygoscelis adeliae) to get insight into their foraging behavior and the strategies they use to capture prey. The experiment was conducted in the waters off the coast of Antarctica.
They used video footage and indirect signals, including acceleration of the head and temperature changes in the digestive tract or beak opening movements, to analyze the penguins' feeding behavior, reports BBC.
"We assumed that penguins move their heads relative to their body when they capture prey; this was confirmed by the footage," lead researcher Yuuki Watanabe, from the National Institute of Polar Research in Tokyo, Japan, told BBC.
Watanabe and his colleague Akinori Takahashi found that the penguins' foraging areas are mostly covered in ice. Their primary source of food is two species of krill (Euphausia superb and E. crystallorophias) and Pagothenia borchgrevinki - a type of fish. The flightless birds used different strategies to capture fish or krill.
The video footage showed that the penguins swam upwards to the krill and then made darting movements as they struck the prey. They did not miss the target even once and were able to catch at least two krill per second.
The research team was also surprised to see the penguins capture Pagothenia borchgrevinki despite their ability to get camouflaged. "I was surprised by how the penguins repeatedly captured P. borchgrevinki underneath the sea ice. This fish is known to be well camouflaged," Watanabe told the broadcasting corporation.
The findings of the study appear in the journal of the Proceedings of National Academy of Sciences.