Tui De Roy / Snares Crested penguin (Eudyptes robustus) bathing in freshwater pool, Snares Island, New Zealand Sub-Antarctic Islands. Endemic and vulnerable species.

Wild Wonders of Europe / Lundgren / Pool Frog (Pelophylax lessonae) viewed from below while swimming, underwater around Crisan village, Danube Delta, Romania, June.

Wild Wonders of Europe / Lundgren / Pool frog (Pelophylax lessonae) reflected in waters surface at night, Danube Delta, Romania, June.

Graham Eaton,Graham Eaton / A boy swimming crawl stroke in a pool, Egypt, September 2012. Model released

Steven Kazlowski / Polar bear (Ursus maritimus) underwater view swimming in a pool, Anchorage Zoo, Alaska, USA. No release available.

Cheryl-Samantha Owen / Cape gannet (Morus capensis) coated in oil swimming in pool at the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB). Vulnerable species. Third place in Mankind and Nature p...

Cheryl-Samantha Owen / Cape gannet (Morus capensis) coated in oil swimming in pool at Southern African Foundation for the Conservation of Coastal Birds (SANCCOB). Vulnerable species. Third place in Mankind and Nature portf...

Cheryl-Samantha Owen / Cape gannet (Morus capensis) coated in oil swimming in pool at the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB). Cape Town, South Africa. Vulnerable species. Third place...

MYN / Piotr Naskrecki / Red spotted / Eastern Newts (Notophthalmus viridescens) swimming; from a vernal pool, Woburn, Massachusetts, USA, April, digital composite. meetyourneighbours.net project

Alex Mustard / A young California sealion (Zalophus californianus) swims in a shallow pool. Los Isotes, La Paz, Mexico. Sea of Cortez, East Pacific Ocean.

Wild Wonders of Europe / Roggo / Alpine newt (Triturus alpestris) chasing a ball of Water fleas in a gravel pit pool, Fribourg, Switzerland, June 2009

Juergen Freund / Fern Pool - a permanent swimming hole surrounded by lush vegetation, Karajini National Park, Western Australia