Krill | Facts, Diet, Habitat & Pictures

Krill | Facts, Diet, Habitat & Pictures

Krill Overview


Krill are small, shrimp-like crustaceans with translucent bodies, allowing their internal structures to be visible. They have elongated bodies, typically measuring around 1 to 2 centimeters in length.

Krill have multiple pairs of jointed legs, including specialized feeding appendages, and their bodies may exhibit a pinkish or reddish hue due to the presence of a pigment called astaxanthin.

Their streamlined form is well-suited for swimming in large swarms, often in the upper layers of the ocean. Krill play a vital role in marine ecosystems as a primary food source for various marine creatures.

Origins And Evolution

Small marine crustaceans trace their origins to the Late Triassic period, approximately 200 million years ago. They belong to the order Euphausiacea and have evolved from ancient shrimp-like ancestors.

Over millions of years, krill have adapted to diverse oceanic environments, developing specialized features like their large, complex compound eyes and unique feeding appendages called thoracopods.

This evolution has enabled them to thrive as a vital component of marine ecosystems, serving as a crucial link in the food chain. Today, populations continue to play a pivotal role in sustaining various marine species, including whales, seals, and seabirds, and remain a vital component of the world's oceans.

Behavior and Lifestyle

It exhibits a highly organized and synchronized lifestyle. They are known for forming massive swarms or aggregations, often numbering in the billions, to protect themselves from predators. Krill are primarily herbivorous, feeding on microscopic phytoplankton using specialized feeding appendages.

They migrate vertically in the water column, moving closer to the surface during the night to feed on phytoplankton and descending to deeper, darker waters during the day to avoid predators. They are a crucial link in marine food webs, serving as a primary food source for many marine species, including whales, seals, and various fish.

Scientific Classification

  • Kingdom: Animalia (Animals)
  • Phylum: Arthropoda (Arthropods)
  • Subphylum: Crustacea (Crustaceans)
  • Class: Malacostraca (Malacostracans)
  • Order: Euphausiacea (Krill)
  • Family: Euphausiidae (Krill Family)


  • Antarctic Ocean
  • North Atlantic Ocean
  • North Pacific Ocean
  • Southern Ocean
  • Indian Ocean
  • Atlantic Ocean
  • Pacific Ocean
  • Arctic Ocean
  • Southern Atlantic Ocean
  • Southern Pacific Ocean

Fast Facts

  • Name: Krill
  • Scientific Name: Euphausiidae spp.
  • Habitat: Cold Oceans
  • Diet: Plankton Consumer
  • Physical Features: Transparent Shrimp
  • Nocturnal: Night Migrator
  • Solitary: Massive Swarms
  • Unique Order: Euphausiacea
  • Lifespan: 2-5 years
  • Conservation Status: Abundant Population
  • Fun Facts: Vital Oceanic Base

Physical Characteristics

  • Color: Transparent Shrimp
  • Skin Type: Exoskeleton Armor
  • Top Speed: Swift Swimmers
  • Lifespan: 2-5 Years
  • Weight: Tiny Crustaceans
  • Length: Small Sizes
  • Age of Sexual Maturity: 1-2 Years
  • Age of Weaning: Larval Stage


Q1: What are krill?

Ans: They are small, shrimp-like marine crustaceans that are vital to marine ecosystems as a food source.

Q2: What is the main diet of krill?

Ans: Primarily feed on phytoplankton, but they also consume small zooplankton and detritus.

Q3: Why are krill important to the marine food chain?

Ans: They are a crucial link in the food chain, serving as a primary food source for various marine animals, including whales, seals, penguins, and seabirds.

Q4: Do krill migrate?

Ans: Yes, it often migrates vertically in the water column, moving closer to the surface at night to feed and descending to deeper waters during the day to avoid predators.

Q5: Are there different species of krill?

Ans: Yes, there are numerous species of krill, each with specific adaptations and distributions.

Q6: Do krill have any predators?

Ans: Yes, they have natural predators, including fish, seabirds, penguins, and marine mammals like whales and seals.

Q7: Can humans consume krill?

Ans: Yes, they are harvested for their oil and protein, which are used in dietary supplements for their potential health benefits.


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