Gary Bell/ Oceanwide / Variegated Jawfish (Opistognathus solorensis) male brooding eggs in mouth, Anilao, Philippines

Gary Bell/ Oceanwide / Variegated Jawfish (Opistognathus solorensis) male brooding eggs in mouth, Anilao, Philippines

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) chick begging for food, on parent's feet. Atka Bay, Antarctica. August.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), two chicks aged six to eight weeks brooding on parents' feet, one vocalising. Atka Bay, Antarctica. September.

David Fleetham / Ring-tailed cardinalfish (Ostorhinchus aureus), male protecting and incubating eggs in mouth, Philippines.

Alex Mustard / Tiger cardinalfish (Cheilodipterus macrodon) male mouth brooding a clutch of eggs behind his sharp teeth. Gubal Island, Egypt. Strait Of Gubal, Red Sea.

Bert Willaert,Bert Willaert / Portrait of a Darwin's Frog (Rhinoderma darwinii) Chile, Vulnerable species

Doug Perrine / Ring-eye jawfish male expels larvae after brooding eggs in mouth for a week {Opistognathus sp} Borneo (Non-ex).

Georgette Douwma / Gold specs jawfish male incubating eggs in mouth, unable to feed {Opistognathus sp} Sangalakki, Indonesia

Pascal Kobeh / Cardinalfish (Apogonidae) male mouth brooding eggs at night, on sea floor. Flores Sea, Indonesia.

Tony Wu / Striped poison-fang blenny mimic (Petroscirtes breviceps) male inside bivalve shell, guarding eggs laid by different females adhered to inside of shell. Shizuoka Prefecture, Honshu, Japan. June.

Tony Wu / Spotnape cardinalfish (Ostorhinchus notatus) pair, male taking cluster of fertilised eggs into mouth to brood. Shizuoka Prefecture, Honshu, Japan. June.