Emanuele Biggi / Peruvian Tarantula (Pamphobeteus sp.) and Humming Frog (Chiasmocleis royi) together, Los Amigos Biological Station, Madre de Dios, Amazonia, Peru. These species have a commensal relationship. The tara...

Emanuele Biggi / Peruvian Tarantula (Pamphobeteus sp.) adult, walking over Humming Frog (Chiasmocleis royi) without preying on it. Los Amigos Biological Station, Madre de Dios, Amazonia, Peru. These species have a com...

Tui De Roy / Galapagos Lava Lizard (Microlophus albemarlensis) on Marine Iguana (Amblyrhynchus cristatus), Punta Espinosa, Fernandina Island, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Lava Lizard (Microlophus albemarlensis) on Marine Iguana (Amblyrhynchus cristatus), Punta Espinosa, Fernandina Island, Galapagos Islands, Ecuador

Tony Wu / Humpback whale (Megaptera novaeangliae) adult female at rest. The tubercles on the whale's head are clearly visible, as are the barnacles (Coronula diadema), whale lice (Cyamus boopis), and hairs on t...

Franco Banfi / Devilray (Mobula tarapacana) swimming near the surface with remoras, Ambrosio dive site, Santa Maria Island, Azores, Portugal, Atlantic Ocean

Pete Oxford / Whale Shark (Rhincodon typus) and Golden Trevally (Gnathanodon speciosus) school, Cenderawasih Bay, West Papua, Indonesia

Alex Mustard / Group of predators hunting together, in an example of 'Nuclear foraging'. The Moray eel (Gymnothorax javanicus) flushes out prey, and is followed by a Napolean wrasse (Cheilinus undulatus) and a Bluef...

Staffan Widstrand / Wild Wonders of China / Crested myna starlings (Arcidotheres cristatellus) sitting on domestic waterbuffaloes (Bubalus domesticus), Poyang Ho Lake, Jiangxi province, China

Staffan Widstrand / Wild Wonders of China / Crested myna starlings (Arcidotheres cristatellus) sitting on domestic waterbuffaloes (Bubalus domesticus), Poyang Ho Lake, Jiangxi province, China

Georgette Douwma / Green turtle (Chelonia mydas) with two large remoras (Echeneis naucrates) attached to its carapace, at rest on artificial reef. Mabul, Malaysia.

Roland Seitre / Blackish cinclodes (Cinclode fuligineux) on beach with Southern Elephant-Seal (Mirounga leonina). This species feeds on dead skin of the seal. Falklands Islands.