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83. Blue Whale

Balaenoptera musculus


The blue whale is the largest animal alive today and one of the largest animals ever – rivalled only by the largest dinosaurs; the titanosaurs.

The species is thought to feed almost exclusively on small, shrimp-like, crustraceans called krill. In the summer feeding areas, individuals may consume as much as 4 tonnes of krill each day. Blue whales have the deepest voice of any animal, and their vocalisations carry for thousands of miles underwater, allowing them to communicate across vast oceans as frequencies below the range of human hearing. For centuries the blue whale was safe from exploitation because of its sheer size and speed. However, the species was driven to the brink of extinction following the development of modern whaling techniques. They are also under threat from shipping practices, with occasional ship strikes, but also the disturbances of ship traffic and ship noise, though the impact of these is not fully known.

  • Order: Cetartiodactyla
  • Family: Balaenopteridae
  • Population: <5,000
  • Trend: increasing
  • Size: 25-27m
  • Weight: up to 190,000kg

EDGE Score

EDGE Score: 5.18 (?)
ED Score: 21.22 (?)
GE / IUCN Red List (?)
Not Evaluated Data Deficient Least Concern Near Threatened Vulnerable Endangered Critically Endangered Extinct in the Wild Extinct


The blue whale occurs in the Arctic, Atlantic, Indian and Pacific Oceans, from the tropics to the drift ice of polar waters.

Habitat and Ecology

Blue whales inhabit the open ocean in both cold and temperate waters. Often found along the continental shelf edge and near polar ice. They are thought to feed almost exclusively on small, shrimp-like crustaceans (krill). They are usually seen alone, or in small groups of two to three individuals, although groups of up to 60 may form in areas where food is plentiful. Blue whales are migratory, with most individuals spending the summer feeding in high-latitude regions and returning to warmer waters in the winter for mating and calving.

Find out more

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Conservation Actions

For each key category of conservation action, we calculated a conservation attention score based on expert information. In this graph, a higher score means the action is being carried out more intensively over more of the species range. The colour shows how important each action is considered to be for the conservation of this species.

Engaging stakeholders
Addressing threats
Status of knowledge
Management plan
Capacity building
Behaviour change
Awareness raising
  Score: 100 means the activity occurs at high level across more than 75% of the species range
Very Low

Overall Conservation Attention

We combined all of the expert information on conservation actions to calculate an overall conservation attention score for this species. Please help us to reach our goal of establishing dedicated conservation attention at “High” levels for all EDGE species.

Very Low Low Medium High

More information

Recent studies have grouped all possible conservation activities for any species into nine key categories (Washington et. al 2015). For each action, we asked experts for each species to assess the extent to which that action is being carried out and how much of the species’ range that action occurs in. For each action we used these two pieces of information to calculate the conservation attention score per action. A score of 100 means that the action is being carried out to a high level across at least 75% of the species range. We then combined the scores for all actions into an overall conservation attention score for the species. The experts also judged how important each category was to the conservation of that particular species.

This wordcloud illustrates the threats facing this species. The size of each word indicates the extent of a species range that is affected by that threat (larger size means a greater area is affected). The colour of the word indicates how much that threat impacts the species (darker shades of red mean the threat is more severe).

Habitat change Fishing

Threat wordcloud key:

Small area affected
Large area affected
Least severe
Most severe
Severity unknown
Source: The IUCN List of Threatened Species. Version 2017.1.
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