It's truly amazing how animals can adapt so quickly to any change in their environment. Much of it stems back to global warming. However, in this article that I found from the National Geographic site, the change here, is due to hunting whales and seals! Although the change is not terrible for the penguins, it sure is for the whales and seals.
Apparently, penguins' main source of food was fish up until the last 200 years. The increase in whale and seal hunting near Antarctica has caused there to be an abundance of krill, also known as shrimp-like crustaceans. Biologists Steve Emslie and William Patterson analyzed 220 penguin fossils over the past 38,000 years.
"The proportions of certain forms of carbon and nitrogen in the eggshells tell the researchers what type of food the penguins ate in the days before laying their eggs." From their findings, they were able to discern that the penguins relied heavily on fish. Fish are actually higher up on the food chain than krill. Krill, however, is clearly preferred by Adelie Penguins, and is a great energy source. Now, more recently, krill is back on a decline, while fish are in abundance. This is due to the warming temperatures, lessening the sea ice, which holds algae for the krill to feed on. Lucky for Adelies, they adapt easily to environmental changes, especially when fishers have been taking krill to use in fish farms as food. I found this amazingly beautiful picture of Antarctica and just had to include it in this post!
Roach, John. (2007). Penguins Changed Diet Due to Whaling, Study Suggests. National Geographic News. Retrieved on March 20, 2008, from http://news.nationalgeographic.com/news/2007/07/070720-penguins-whales.html
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