Blue whale (Balaenoptera musculus). A blue whale tail as it leaves the water prior to diving. Gulf of California.

Blue whale (Balaenoptera musculus). The back and blowholes of a blue whale at dawn. Gulf of California.

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 making good speed pushes water before it. Gulf of California.

Blue whale (Balaenoptera musculus). The tail of a blue whale against an evening sky. Blue whale tails can be over 20ft across. Gulf of California.

Blue whale (Balaenoptera musculus). The huge tail stock of a blue whale showing lots of round scars thought to be from cookie cutter sharks. The tiny dorsal fin is clealry visible to the left. 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.

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). 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.

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

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

Blue whale (Balaenoptera musculus) fluking to dive, Monterey Bay, California, USA

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 to blow hole, Gulf of California, Mexico.

Blue whale, (Balaenoptera musculus), fluking up to dive, Monterey Bay, California, USA

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

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.

Blue Whale (Balaenoptera musculus) Adult fluke-up dive - note the damage to the right fluke. Gulf of California (Sea of Cortez), Mexico.

Whale-watchers photographing a Blue whale (Balaenoptera musculus) as it surfaces close by with the blow visible. Husavik, Iceland

Blue whale (Balaenoptera musculus). A blue whale tail enthralls watching tourists. Gulf of California.