What Do Krill Look Like?
Sometimes referred to as the "potato chips of the sea," krill play an essential role in the underwater world by feeding seabirds and countless marine animals from small fish to blue whales. Although tiny, these sea creatures have been estimated to have a total weight of up to 500 million tons in Antarctica alone; a number that National Geographic claims rivals the total weight of humans on Earth. Sheer mass is essential when they're the primary source of food within the ecosystem.
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Species
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Krill are classified as part of the crustacean family along with shrimp. They are invertebrates, meaning they lack a backbone or spinal column. Instead, their bodies have an outer shell know as an exoskeleton. As herbivores, the tiny creature's diet consists of even smaller organisms such as ice algae, phytoplankton and zooplankton.
Features
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To the untrained eye, krill look a lot like small shrimp. They shed, or molt, their exoskeleton multiple times as they grow larger. However, they differ from other crustaceans such as crabs and lobsters through their lack of claws. Instead, they have short, simple, insect-like legs referred to as "swimmerets" used to navigate and gather food. They're equipped with large, solid black eyes and two sets of antennas serving as tactile and olfactory sensors that allow them to feel and smell.
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Size
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Krill vary in size, ranging from 1/2 to 5 ½ inches in length. Their average weight is only about one gram, leaving them highly vulnerable, but they do have ways of defending themselves. Krill's ability to instantly molt confuses their pursuer, giving them the chance to swim away. They travel in massive groups, known as swarms, which also protect them from smaller predators. These swarms are so dense that they can sometimes be seen from space.
Color
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Like their fellow crustaceans, krill are predominantly red, pink or orange, but parts of their body will appear semi-translucent. This allows you to see through their exoskeleton, revealing shadows of their inner organs. Parts of their innards tend to appear green due to the tiny plants and organisms they consume as part of their diet, yet krill can survive up to 200 days without eating.
Type
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There are currently 85 different types of krill known to mankind. The most common of these is found in Antarctica where they serve as the main staple of the oceanic food chain. The different species vary in size, length and geographic locations. Some reside in the abysmal deep while others prefer more shallow waters.
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