Doug Perrine / Bryde's whale {Balaenoptera brydei / edeni} with throat pleats expanded after feeding on baitball of Sardines {Sardinops sagax} off Baja California, Mexico, Eastern Pacific Ocean. Veolia Environnement...

Brent Stephenson / Humpback whale (Megaptera novaeangliae) surfacing whilst lunge-feeding, showing the extended throat pleats, Neko Harbour, Antarctic Peninsula, Antarctica, January.

Doug Perrine / Bryde's whale (Balaenoptera brydei / edeni) with throat pleats expanded after engulfing part of a school of Sardines, off Baja California, Mexico (Eastern Pacific Ocean)

Doug Perrine / Humpback whale (Megaptera novaeangliae) adult female with acorn barnacles are attached to her lower jaw. Image showing throat pleats, and pectoral fin, near Lahaina, in the A'u A'u Channel, off West M...

Graham Eaton / Sea cliffs, geological section through Cambrian and Ordovician sedimentary rocks with faulted monocline fold structure. Rocks include Nant-pig Musdstones, Abersoch, Gwynedd, Wales, UK

Graham Eaton / Cilan Headland, a headland of folded and tilted Cambrian and Ordovician age sedimentary rocks, Abersoch, Gwynedd, Wales, UK, August 2016.

Graham Eaton / Steeply dipping beds of Silurian age turbidite sediments, Clarach Bay, Aberystwyth, Wales, UK, September 2014.

Nick Upton / Chevron folds of Sandstone and shale rock layers in Millook Haven cliffs, Cornwall, UK, April 2014.

Nick Upton / Chevron folds of Sandstone, mudstone and black shale rock layers in Millook Haven cliffs, Cornwall, UK, April 2014.

Nick Upton / Chevron folds of Sandstone and shale rock layers in Millook Haven cliffs, Cornwall, UK, April 2014.

Mark Carwardine / Blue whale (Balaenoptera musculus) rolling at the surface showing an eye and throat pleats, Baja California, Sea of Cortez (Gulf of California), Mexico, Endangered species

Mark Carwardine / Blue whale (Balaenoptera musculus) rolling at the surface showing an eye and throat pleats, Baja California, Sea of Cortez (Gulf of California), Mexico, Endangered species