Eric Baccega / Chimpanzee (Pan troglodytes) female aged 37 years, portrait. Beauval Zoo Parc, France. Captive.

Heather Angel / Lousewort (Pedicularis oxycarpa), a hemi-parasite on grass. Pollinated by bumblebees through buzz pollination, rapid vibration of flight muscles releases pollen in the flower. Near Barkham, Sichuan Pr...

Ashley Cooper / Middle aged man paddling in an inflateable kayak on Ullswater, Lake District, UK. July 2014

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chicks flapping wings to strengthen muscles, Adelie Land, Antarctica, January.

Frederique Olivier / Panning shot of Emperor penguin (Aptenodytes forsteri) chicks flapping wings, strengthening muscles, Adelie Land, Antarctica, January.

Floris van Breugel / High speed exposure of a Fruit fly (Drosophila melanogaster) taken through a microscope. In this image flight muscles express a genetically engineered protein called GCaMP, which fluoresces green in t...

Floris van Breugel / Fruit fly (Drosophila melanogaster) tethered in LED illuminated chamber which stimulates moving visual patterns. Behind the fly is a camera, which is used to record its wing beat amplitude a rough me...

Christian Ziegler / Leaf-nosed Bat (Phyllostomidae) flight muscles and blood vessels in the wing membrane, Smithsonian Tropical Research Station, Barro Colorado Island, Panama

Mark Moffett / Leafcutter Ant (Atta sexdens) soldier, close-up, the largest worker in many leafcutter colonies specialize in defense, their enlarged heads contain massive adductor muscles to work their powerful jaws...

Paul D Stewart / Reconstruction of the neanderthal 'Man of Chapelle-Aux Saints' by Mr. Kupka (scientifically advised by Marcellin Boule) for the Illustrated London News (ILN), Feb 27th, 1909. This image stuck with the...

Paul D Stewart / Reconstruction of the neanderthal 'Man of Chapelle-Aux Saints' by Mr. Kupka (scientifically advised by Marcellin Boule) for the Illustrated London News (ILN), Feb 27th, 1909. This image stuck with the...

Christian Ziegler / Leaf-nosed Bat (Phyllostomidae) flight muscles and blood vessels in the wing membrane, Smithsonian Tropical Research Station, Barro Colorado Island, Panama