Wild Wonders of Europe / E. Haarberg / Male Black grouse (Tetrao tertrix) displaying, expiring warm air on a cold morning, Bergslagen, Sweden, April 2009

Ross Hoddinott / Marbled white butterfly (Melanargia galathea) resting among tall grasses and bathed in warm, early morning sunlight, Volehouse Moor, Devon, UK. July.

Ross Hoddinott / Marbled white butterfly (Melanargia galathea) roosting among tall grasses at sunrise and bathed in warm, early morning sunlight, Volehouse Moor, Devon, UK. July.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) colony with with creche of huddling chicks, Atka Bay, Queen Maud Land, Antarctica. October.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) chick aged six to eight weeks sheltering on parent's feet, portrait. Atka Bay, Antarctica. September.

Peter Bassett / King penguin (Aptenodytes patagonicus) standing on its heels on a rock to keep its feet warm, Salisbury Plain, South Georgia.

Frederique Olivier / Hungry Adelie penguin (Pygoscelis adeliae) chick pecking at a rock before tucking into its parent to keep warm, with a dead chick in the foreground, Antarctica

Floris van Breugel / Monarch butterflies (Danaus plexippus) over winter on Eucalyptus and Monterey Cypress trees near Pismo Beach, San Luis, California, USA December.. When temperatures warm up enough, they will embark on...

Roy Mangersnes / Marine iguana (Amblyrhynchus cristatus) feeding in deep water to find algae, off the coast of Fernandina island on Galapagos. April 2016. Much of the algae on coast and at shallower depths have been k...

Roy Mangersnes / Marine iguana (Amblyrhynchus cristatus) feeding in deep water to find algae, off the coast of Fernandina island on Galapagos. April 2016. Much of the algae on coast and at shallower depths have been k...

Roy Mangersnes / Marine iguanas (Amblyrhynchus cristatus) basking on rock next to skeleton of one which starved to death. Unusually warm El Nino waters have killed a lot of the algae which is the food for these iguana...