Blue whale (Balaenoptera musculus). The massive vertebrae of a blue whale, seen here from the rear. Gulf of California.

Blue whale (Balaenoptera musculus). A blue whale footprint. Gulf of California.

Blue whale (Balaenoptera musculus). The typically mottled skin colouring of a blue whale and an equally typical dorsal fin. Gulf of California.

Blue whale (Balaenoptera musculus). A typical blue whale blow. Gulf of California.

Blue whale (Balaenoptera musculus). The blows of two blue whales, an adult and a juvenile. Gulf of California.

Blue whale (balaenoptera musculus). A blue whale tail. Gulf of California.

Blue whale (Balaenoptera musculus). In the early light and silky sea a gentle blue whale barely makes a ripple. Gulf of California.

Blue whale (Balaenoptera musculus). Tourists watch the sedate progress of a blue whale as it circles their boat, the animal is feeding. Gulf of California.

Blue whale (Balaenoptera musculus). The tail of a blue whale raised way out of the water before diving deep. The typical skin colouring is also visible. Gulf of California.

Blue whale (balaenoptera musculus). The tail of a blue whale. Gulf of California.

Blue whale (Balaenoptera musculus). Moving at speed a blue whale creates a massive bow wave, seen here as the whale surfaces. Gulf of California.

A blue whale (Balaenoptera musculus) surfaces alongside a panga with tourists. The tiny dorsal fin is visible to the left of the white hat. Gulf of California.

Blue Whale (Balaenoptera musculus) fluke-up dive in the middle Gulf of California (Sea of Cortez), Mexico.

Blue Whale (Balaenoptera musculus). Looking along back-bone to blow hole, Gulf of California, Mexico.

Blue Whale (Balaenoptera musculus) surfacing in the middle Gulf of California (Sea of Cortez), Mexico.

Blue Whale (Balaenoptera musculus) fluke-up dive at sunset in the offshore waters of Santa Monica Bay, California, USA.

Blue Whale (Balaenoptera musculus). Looking along back-bone & showing small dorsal fin, Gulf of California, Mexico.

Blue Whale (Balaenoptera musculus) Adult fluke-up dive. Gulf of California (Sea of Cortez), Mexico.

Two Blue whales, (Balaenoptera musculus), diving together, Monterey Bay, California, USA

Blue whale, (Balaenoptera musculus), fluking up sequence 2/3, Monterey Bay, California, USA

Blue Whale (Balaenoptera musculus) Mother and calf fluke-up dive in the Gulf of California (Sea of Cortez), Mexico.

Blue Whale (Balaenoptera musculus) fluke-up dive in the offshore waters of Santa Monica Bay, California, USA. The blue whale is the largest animal to ever live on planet Earth. Santa Monica Bay, California, USA

Blue whale (Balaenoptera musculus). The tail of a blue whale beneath rugged cliffs. Gulf of California.