Sea Ice Helps Long Foraging Trips of Emperor Penguins

Sea ice plays a significant role in the foraging activity of emperor penguins, a new study reveals.

Using motion detectors that were mounted on emperor penguins, researchers from Fukuyama University, Japan, observed 10 penguins from a colony at Cape Washington in the Ross Sea. They noticed that the penguins depended on sea ice for feeding and breeding, a report in OurAmazingPlanet said.

Until now, it had been difficult for researchers to examine the relationship between sea ice levels and the penguins' foraging activity. But the new monitoring technique has helped them understand this relationship.

Based on their observation, experts found that the emperor penguins spend 66 percent of their time diving in the sea in search of food. They noticed that the penguins were able to dive continuously throughout day and night with 24 hours of sunlight, while taking short rest periods on the sea ice. Such short breaks helped them carry on their long foraging trips, the researchers state.

"Emperor penguins are a unique ecology, because they are the largest species of penguins and they have the biggest and largest chicks, so they have to bring [a lot of] food," study author Shinichi Watanabe, an animal ecologist and professor at Fukuyama University in Hiroshima, told OurAmazingPlanet.

"Also, the distance between the breeding colony and the foraging site is very long, so they need more food," he said.

Researchers infer that the penguins might be taking short rests on the ice in between long dives to wait for others to form a group. Diving in groups helps reduce the risk of attack from predators like leopard seals.

Researchers hope the study will help in understanding the impact of climate change on emperor penguin colonies. They warn that the change in the sea ice pattern might affect penguins' foraging behavior.

The findings of the study, "Activity Time Budget during Foraging Trips of Emperor Penguins", are published in the journal PLoS ONE.