Heather Angel / Man using pole to propel bamboo raft on Lijang / Li River, Karst peaks beyond. At dawn, Lijiang River Scenic Zone, Yangshuo county, Guangxi, China.

Rod Clarke / John Downer Produ / Flame scallops (Chlamys) clap their shells together to propel themselves away from predators. (Resolution restriction due to image digitised from film - 'Weird Nature' BBC tv series)

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

Kim Taylor / Great grey slug {Limax maximus} developing within egg. Sequence 8/11. UK.

Peter Nearhos / John Downer Pr / Crocodiles can overcome their huge weight to propel themselves out of water at speed (Resolution restriction - image digitised from film, 'Weird Nature' tv series)

Franco Banfi / Mahi-mahi (Coryphaena hippurus) school hunting Pacific sardine (Sardinops sagax) bait ball. Two Mahi-mahi propel themselves towards the shoal, catching two fish. California sea lions (Zalophus califor...