What does krill mean?
Krill are small, shrimp-like marine crustaceans, most famously the Antarctic krill that occur in enormous swarms throughout the Southern Ocean. Although each animal is only a few centimetres long, their collective biomass supports whales, seals, penguins, fish, and other predators. They feed on microscopic plankton and have complex feeding and migration behaviours, often gathering in dense aggregations that can move across substantial areas of ocean. Krill also have a major role in commercial marine ecosystems and have been the subject of research into climate change, fishing pressure, and the effects of reduced sea ice. In general English, “krill” most often refers to the Antarctic species, while the wider biological category is sometimes called euphausiids. The word is also notable because its singular and plural forms are identical: scientists speak of one krill, a few krill, or a large mass of krill.
nounAny of various small, shrimp-like marine crustaceans of the family Euphausiidae, especially the abundant Antarctic krill found in cold Southern Ocean waters. Krill swim in dense groups and form a major part of the diet of whales, penguins, seals, and many other animals.
- Any small, shrimp-like marine crustacean of the family Euphausiidae, particularly the Antarctic krill, a hugely abundant species in the Southern Ocean.
"Huge swarms of Antarctic krill sustain the feeding populations of whales and penguins throughout the Southern Ocean."
"Researchers tracked the movement of a dense krill swarm beneath the Southern Ocean."
"The whale filtered krill from the water as it surfaced beside the ice shelf."
The form is unchanged in the plural and can refer to one or more animals.
"Scientists observed the krill migrating near the surface."
A single Antarctic krill is tiny, but immense swarms can contain billions of animals and support some of the ocean's largest predators.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does krill come from?
The English word was borrowed from Norwegian, where krill was used for small fish and related sea creatures. Its wider ultimate origin is uncertain, although it belongs to a group of Scandinavian words associated with small aquatic animals. By the nineteenth century, the term had entered zoological usage for crustaceans related to shrimp.
How krill is actually used
The plural form is the same as the singular form. In scientific and conservation contexts, the unqualified term commonly refers specifically to Antarctic krill.
Easily confused with krill
Krill are a distinct group of crustaceans, whereas shrimp belong to other groups of decapod crustaceans.