New Study Reveals Penguins Eat Jellyfish !

Up until recently, we thought the diet of penguins comprised only of fish, shrimps and crustaceans. But now, a new study by researchers from the National Institute of Polar Research in Tokyo, Japan comes to add one more item on the menu, jellyfish!

For this study, the scientists mounted 106 penguins from 4 different species with tiny cameras.  After examining over 350 hours of footage, they witnessed many instances in which penguins attacked and ate jellyfish or other gelatinous animals. In the past, studies indicated this happened only by accident when penguins hunted other food sources. However, the new footage reveals this was 100 % intentional: 

 Video logs confirmed that penguins targeted gelatinous animals for meals; the birds did not merely ingest them accidentally, while aiming for fish or other prey. [1]

Photo showing Diplulmaris Antarctica jellyfish and Adélie (Pygoscelis adeliae) penguin (Credit) 

The species that were mounted with cameras were: 

1. Adélie penguins (Pygoscelis adeliae), 
2. Yellow-eyed penguins (Megadyptes antipodes)
3. Magellanic penguins (Spheniscus magellanicus), 
4. Little penguins (Eudyptula minor)
   

Here's a video that was released with the study, showing 4 individuals preying on jellies and other gelatinous sea creatures:

(DTUBE alternative link, uploaded from my alt-account)

The study suggests that only a small part of the caloric needs is covered by eating jellies and other gelatinous creatures, approximately  1 to 2 % depending on the penguin species. Still, the researchers say they were quite surprised by this jelly-eating behavior: 

"It is hard to believe that penguins, which are endothermic animals and thus need fair amounts of energy from their food to keep their bodies warm, could find any benefit in eating relatively energy-poor prey like jellyfish, especially in freezing Antarctic waters.Crustaceans, and more so fish, contain much more energy per gram, and seem much more adequate to satisfy the energy demand of penguins.  " said Jean-Baptiste Thiebot, lead author of the study, to National Geographic.  [3]

What is even more interesting is that for some reason penguins appear to have a preference for carnivorous gelatinous animals, like cnidaria jellyfish and "comb jellies" (Ctenophora). For unclear reason, they don't seem to pursue "vegetarian" jellies, for example salps, which feed on phytoplankton. 

Why penguins feed on gelatinous animals is still unknown. Some theorize that jellies are eaten as a food of last resort. However,  Thiebot believes it's more probable that they are a just quick "snack" that helps penguins fuel their long trips as they search for other, more calorie-dense items. Or maybe jellyfish have a higher nutritional value than we curently think. Or maybe they just do it just because they like their taste! All we know is that they don't seem to suffer from any side-effects after consuming these toxic animals.

One thing is for sure. Penguins can now be officially added to the list of confirmed jellyvores!

Diagram showing the point  were the cameras were placed (credit)

Abstract

The study is available online ahead of print in the Ecological Society of America's peer-reviewed journal Frontiers in Ecology and the Environment. Here's the abstract:

Jellyfish and other pelagic gelatinous organisms (“gelata”) are increasingly perceived as an important component of marine food webs but remain poorly understood. Their importance as prey in the oceans is extremely difficult to quantify due in part to methodological challenges in verifying predation on gelatinous structures. Miniaturized animal-borne video data loggers now enable feeding events to be monitored from a predator's perspective. We gathered a substantial video dataset (over 350 hours of exploitable footage) from 106 individuals spanning four species of non-gelatinous-specialist predators (penguins), across regions of the southern oceans (areas south of 30°S). We documented nearly 200 cases of targeted attacks on carnivorous gelata by all four species, at all seven studied localities. Our findings emphasize that gelatinous organisms actually represent a widespread but currently under-represented trophic link across the southern oceans, even for endothermic predators, which have high energetic demands. The use of modern technological tools, such as animal-borne video data loggers, will help to correctly identify the ecological niche of gelata. [2]

Feel free to check the links down below to learn more about this research!

References

1. Sciencedaily.com/releases/2017/09/170925163223.htm
2. Onlinelibrary.wiley.com/doi/10.1002/fee.1529/abstract
3. News.nationalgeographic.com/2017/09/penguins-eat-jellyfish-unexpected-prey/
4. Eurekalert.org/multimedia/pub/151609.php

My dear readers, thank you for reading today's article. Hopefully, you found it interesting enough to follow me, @trumpman. You may also want to check my strange animal series where you get to discover some of the world's weirdest animals!  Here are the last 3 weirdos of the series: 

1. Cymothoa exigua: The Parasite That Turns Into A Tongue ?!?!
2. 8 Strange Animal Stuff I Learned The Past Few Days
3. New Cave Dwelling Animal Discovered With The Help Of Smelly Cheese

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