How large can blue whales get?

Blue whales reach confirmed maximum lengths of about 29.9–30.5 m (98–100 ft) and can weigh up to roughly 190–200 tonnes.

What do blue whales eat?

They are filter feeders whose diet consists almost exclusively of krill.

Are blue whales threatened?

Yes; the IUCN lists the blue whale as Endangered (assessment year 2018), and they face threats including ship strikes, pollution, ocean noise, and climate change.

Do blue whales migrate?

Many populations migrate between polar summer feeding areas and tropical winter breeding grounds, though some populations show year-round residency or partial migration patterns.

How do blue whales communicate?

Blue whales vocalize at very low frequencies, with fundamental frequencies around 8–25 Hz; vocalizations vary by region, season, behavior, and time of day.

When did hunting of blue whales stop?

Widespread hunting was curtailed after the International Whaling Commission banned blue whale hunting in 1966.

How social are blue whales?

They are generally solitary or occur in small groups and have no well-defined social structure aside from mother–calf bonds.

How many subspecies are recognized?

Four subspecies are recognized, with a Chilean population that may represent a possible fifth.

Where to See Blue Whale While Diving

The blue whale (Balaenoptera musculus) is a baleen whale and the largest marine mammal in the rorqual family. Individuals reach confirmed lengths up to about 29.9–30.5 m and can weigh up to about 190–200 tonnes. Their long, slender bodies are various shades of greyish-blue above and somewhat lighter underneath. Four subspecies are recognized across ocean basins, with at least one additional population off Chile that may represent a fifth. Blue whales generally migrate between summer feeding areas near the poles and winter breeding grounds nearer the tropics, although some populations show year-round residency or partial (age- or sex-related) migration. They are filter feeders that consume almost exclusively krill, are typically solitary or occur in small groups, and show strong mother–calf bonds. Blue whales vocalize at very low frequencies (fundamental frequency roughly 8–25 Hz), with calls that vary by region, season, behavior, and time of day. The species was hunted heavily until mid-20th century whaling bans; it is listed as Endangered by the IUCN and continues to face threats from ship strikes, pollution, ocean noise, and climate change.

Blue whales were heavily hunted until mid-20th century and remain listed as Endangered; current threats include ship strikes, pollution, ocean noise, and climate change.

Generally migrate between summer feeding areas near the poles and winter breeding grounds near the tropics; some populations show year-round residency or partial/age- and sex-based migration.

At the country level, the clearest linked starting points on this guide currently point to Canada for divers looking for blue whales.