Ole Jorgen Liodden / Magnificent Frigatebird (Fregata magnificens) male displaying, red throat pouch inflated. Galapagos

Patrick Morris / Magnificent frigate bird {Frigata magnificens} pair on nest, male displaying with red throat pouch inflated, Genovesa Is, Galapagos

PREMAPHOTOS / Aquatic anole male lizard displaying, rainforest, Costa Rica

Rod Williams / Golden poison dart frog (Phyllobates terribilis) with throat pouch / vocal sacs expanded. Captive occurs Colombia. Endangered species

Brent Stephenson / Great Frigatebird (Fregata minor) male in flight against a blue sky, showing underwing and deflated throat-pouch. Ducie Island, Pitcairn Group, September.

Brent Stephenson / Great Frigatebird (Fregata minor) male in flight, showing underwing and deflated throat pouch. Motu Tunga, Tuamotus, French Polynesia, November.

Brent Stephenson / Great Frigatebird (Fregata minor) male in flight, showing underwing and deflated throat pouch. Motu Tunga, Tuamotus, French Polynesia, November.

Staffan Widstrand / Magnificent Frigate (Fregata magnificens) male displaying by inflating his throat pouch. North Seymour, Galapagos, Ecuador, April.

Barrie Britton / Male Magnificent frigate bird (Fregata magnificens) displaying with inflated throat pouch. Frigate Bird Sanctuary, Barbuda. Taken during filming for BBC tv Series "Secrets of the Caribbean" October...

Edwin Giesbers / Flying Dragon / Lizard (Draco volans) with throat pouch extended, standing on tree branch, Sarawak, Borneo, Malaysia

Andrew Walmsley / Male Siamang gibbon (hylobates / Symphalangus syndactylus) vocalising, with throat pouch extended, Captive, New Zealand, Endangered species

Andrew Walmsley / Male Siamang gibbon (hylobates / Symphalangus syndactylus) vocalising, with throat pouch extended, Captive, New Zealand, Endangered species