Tim Laman / Harlequin Tree Frog (Rhacophorus pardalis) in the air with webbed feet spread to glide, Danum Valley Conservation Area, Sabah, Borneo, Malaysia

Nick Garbutt / Harlequin Tree Frog (Rhacophorus pardalis). Danum Valley, Sabah, Borneo

Nick Garbutt / Harlequin Tree Frog {Rhacophorus pardalis} portrait, Danum Valley, Sabah, Borneo.

Pete Oxford / Harlequin Poison Arrow Frog {Dendrobates histrionicus} Ecuador

Pete Oxford / Pebas stubfoot toad (Atelopus spumarius) captive occurs in the Amazon Basin. Vulnerable species.

Nick Garbutt / Harlequin tree frogs (Rhacophorus pardalis) in amplexus, gathered at temporary breeding pool formed after rain. Danum Valley, Sabah, Borneo.

Chris Mattison / Harlequin poison dart frog (Oophaga histrionica), captive, occurs in Ecuador

Roland Seitre / Harlequin Poison Dart Frog (Oophaga histrionica), yellow spotted morph. Captive, Cali Zoo, Cali, Colombia.

Roland Seitre / Harlequin Poison Dart Frog (Oophaga histrionica), red morph. Captive, Cali Zoo, Cali, Colombia.

Roland Seitre / Harlequin Poison Dart Frog (Oophaga histrionica), red spotted morph. Captive. Cali Zoo, Cali, Colombia.

Roland Seitre / Harlequin Poison Dart Frog (Oophaga histrionica), orange morph. Captive. Cali Zoo, Cali, Colombia.

Roland Seitre / Harlequin Poison Dart Frog (Oophaga histrionica). Captive. Cali Zoo, Cali, Colombia.

Roland Seitre / Harlequin Poison Dart Frog (Oophaga histrionica). Captive. Cali Zoo, Cali, Colombia.

Roland Seitre / Harlequin Poison Frog (Oophaga histrionica). Captive. Cali Zoo, Cali, Colombia.

Roland Seitre / Grenouille Harlequin Frog (Atelopus sp.), a newly discovered species. Captive. Cali Zoo, Cali, Colombia, 2010.

Jouan & Rius / Harlequin tree frog (Rhacophorus pardalis), Gunug Gading NP, Borneo, Sarawak, Malaysia

Tim Laman / Harlequin treefrog (Rhacophorus pardalis) on trunk in rainforest, Danum Valley Conservation Area, Sabah, Borneo, Malaysia

Tim Laman / Harlequin treefrog (Rhacophorus pardalis) on trunk in rainforest, Danum Valley Conservation Area, Sabah, Borneo, Malaysia

Tim Laman / Harlequin treefrog (Rhacophorus pardalis) on leaf in rainforest, Danum Valley Conservation Area, Sabah, Borneo, Malaysia

Tim Laman / Harlequin treefrog (Rhacophorus pardalis) on leaf litter on ground, Bako National Park, Sarawak, Malaysia, Borneo

Tim Laman / Harlequin Treefrog (Rhacophorus pardalis) on leaf, Bako National Park, Sarawak, Malaysia, Borneo

Tim Laman / Harlequin Treefrog (Rhacophorus pardalis) on leaf, Bako National Park, Sarawak, Malaysia, Borneo

Tim Laman / Close up of webbed foot of Harlequin treefrog (Rhacophorus pardalis) Bako National Park, Sarawak, Malaysia, Borneo

Tim Laman / Harlequin treefrog (Rhacophorus pardalis) on leaf, Bako National Park, Sarawak, Malaysia, Borneo

Stephen Dalton / Green mosaic / Rancho grande harlequin frog (Atelopus cruciger) Henri Pittier NP, Venezuela, South America, Critically endangered, thought extinct until a gravid female was found in 2008

Tony Heald / Harlequin Tree Frog (Rhacophorus pardalis) on leaf of rainforest tree, Danum Valley, Sabah, Borneo, September

Tony Heald / Harlequin Tree Frog (Rhacophorus pardalis) Sukau, Sabah, Borneo, September

Tony Heald / Harlequin Tree Frog (Rhacophorus pardalis) on stem of rainforest plant, Danum Valley, Sabah, Borneo, September

Nick Garbutt / Harlequin Tree Frog (Rhacophorus pardalis). Danum Valley, Sabah, Borneo.

Nick Garbutt / Harlequin Tree Frog (Rhacophorus pardalis). Danum Valley, Sabah, Borneo.

Nick Garbutt / Harlequin Tree Frog (Rhacophorus pardalis). Danum Valley, Sabah, Borneo

Barry Mansell / Harlequin frog (Atelopus various) Costa Rica

Pete Oxford / Harlequin poison arrow frog {Dendrobates histrionicus} Western Ecuador, South America

Pete Oxford / Harlequin poison arrow frog {Dendrobates histrionicus} Western Ecuador

Nick Garbutt / Harlequin Tree Frog {Rhacophorus pardalis} Danum Valley, Sabah, Borneo.

Nick Garbutt / Harlequin Tree Frog {Rhacophorus pardalis} Danum Valley, Sabah, Borneo.

Nick Garbutt / Harlequin Tree Frog {Rhacophorus pardalis} resting on leaf, Danum Valley, Sabah, Borneo.

Doug Wechsler / Harlequin tree frog {Rhacophorus pardalis} Borneo Sarawak, Lanjak-Entimau WS

Pete Oxford / Harlequin frog {Atelopus sp} Amazonia, Ecuador

Pete Oxford / Harlequin frog {Atelopus sp} Amazonia, Ecuador

Pete Oxford / Harlequin frog {Atelopus sp} Amazonia, Ecuador

Nick Garbutt / Harlequin treefrog {Rhacophorus pardalis} Kinbatangan river, Sabah, Borneo

Doug Wechsler / Harlequin treefrog, nocturnal {Rhacophorus pardalis} Lanjak-Entimau WS, Sarawak,

Doug Wechsler / Harlequin tree frog {Rhacophorus pardalis} Rainforest, Sarawak, Borneo

PREMAPHOTOS / Yellow harlequin frog (Atelopus oxyrhynchus), a diurnal species in the rainforests of Venezuela, Critically endangered species

Barry Mansell / Harlequin frog {Atelopus various} Costa Rica

Emanuele Biggi / Panther flying frog (Rhacophorus pardalis) female depositing eggs in nest made of protein rich mucus hanging from leaf, Kubah National Park, Sarawak, Borneo.

Emanuele Biggi / Panther flying frog (Rhacophorus pardalis) females depositing eggs in nest made of protein rich mucus hanging from leaf, Kubah National Park, Sarawak, Borneo.

Joel Sartore / Photo Ark / Extinct Chiriqui harlequin frogs (Atelopus chiriquiensis) preserved in alcohol, Smithsonian Tropical Research Institute, Gamboa, Panama.

Emanuele Biggi / Harlequin frogs (Atelopus varius) in captivity, held in gloved hands at the El Valle de Anton Conservation Centre (EVACC), breeding program, Panama. Critically endangered.

Emanuele Biggi / Harlequin frogs (Atelopus varius) in vivarium in captivity at the El Valle de Anton Conservation Centre (EVACC), breeding program, Panama. Critically endangered.

Emanuele Biggi / Harlequin frogs (Atelopus varius) females in captivity in vivaria at the El Valle de Anton Conservation Centre (EVACC), Panama. Critically endangered.