Dave Watts / Eastern grey kangaroo (Macropus giganteus) with joey in pouch, Australian Capital Territory, Australia, September

Jouan & Rius / Koala (Phascolarctos cinereus) juvenile in tree, Otway National Park, Victoria, Australia

Dave Watts / Platypus {Ornithorhynchus anatinus} swimming underwater Tasmania, Australia. Composite.

Dave Watts / Koala with young in tree {Phascolarctos cinereus} Queensland, Australia

Owen Newman / Female red kangaroo backlit in evening sun {Macropus rufus} Sturt NP NSW Australia

Owen Newman / Female Red kangaroo backlit at sunset {Macropus rufus} Sturt NP New South Wales Australia

Owen Newman / Male Red kangaroos fighting {Macropus rufus} Sturt NP, New South Wales Australia

Ingo Arndt / Head portrait of Eastern grey kangaroo {Macropus giganticus} Australia

David Gallan / Koala (Phascolarctos cinereus) grooming itself in a tree, East Gippsland, Australia, December.

Jurgen Freund / Hand-reared Boongary (Dendrolagus lumholtzi) feeding in a kitchen, Atherton Tablelands, Queensland, Australia.

Jurgen Freund / Hand-reared Boongary (Dendrolagus lumholtzi) descending from a tree and climbing onto its carer's back, Atherton Tablelands, Queensland, Australia.

Pete Oxford / San Lucas marsupial frog (Gastrotheca pseustes) captive, occurs in Ecuadorian Andes.

Dave Watts / Female Western grey kangaroo (Macropus fuliginosus) rolling with a large joey in her pouch, Kangaroo Island, South Australia.

Dave Watts / Female Tamar wallaby (Macropus eugenii) grazing with a joey in her pouch, Kangaroo Island, South Australia.

Dave Watts / Koala (Phascolarctos cinereus), eating Eucalyptus leaves, Victoria, Australia.

Fred Olivier / Black-footed rock wallaby (Petrogale lateralis), Cape range National Park, Exmouth, Western Australia

Suzi Eszterhas / Koala (Phascolarctos cinereus) mother with joey aged eight months, Queensland, Australia, captive.

Suzi Eszterhas / Koala (Phascolarctos cinereus) mother and joey aged sixth months, Queensland, Australia, captive.

Roland Seitre / Buergers' tree-kangaroo (Dendrolagus goodfellowi buergersi) climbing. Currumbin Sanctuary, Queensland, Australia. Captive, endemic to Papua New Guinea. Endangered species.

Roland Seitre / Goodfellow's tree kangaroo (Dendrolagus inustus) feeding. Captive, from New Guinea. Endangered species.

Roland Seitre / Eastern grey kangaroo (Macropus giganteus) herd, Yuraygir National Park, Grafton, New South Wales, Australia.

Jurgen Freund,Jurgen Freund / Mareeba rock-wallaby (Petrogale mareeba) Queensland, Australia

Jurgen Freund / Sugar Glider (Petaurus breviceps) feeding on sap from a tree trunk. Atherton Tablelands, Queensland, Australia

Claudio Contreras / Grayish Mouse Opossum (Tlacuatzin canescens), Maria Magdalena Island, Islas Marias Biosphere Reserve, Sea of Cortez (Gulf of California), Mexico, June.

Andy Rouse / Common wallaroo (Macropus robustus) hopping in late sunlight, Sal Salis, Ningaloo Reef, Cape Range National Park, Western Australia

Andy Rouse / Common wallaroo (Macropus robustus) in late sunlight, Sal Salis, Ningaloo Reef, Cape Range National Park, Western Australia

Andy Rouse / Agile wallabies (Macropus agilis) sparring and fighting, Bamarru Plains, Northern Territories, Australia

Andy Rouse / Agile wallabies (Macropus agilis) sparring and fighting, Bamarru Plains, Northern Territories, Australia

Andy Rouse / Agile wallaby (Macropus agilis) Bamarru Plains, Northern Territories, Australia

Dave Watts / Tasmanian Devil (Sarcophilus harrisii) running blur, Cradle Mountain, Tasmania, Australia

Ingo Arndt / Yellow-footed rock wallaby (Petrogale xanthopus) Australia, December

Dave Watts / Mareeba rock wallaby (Petrogale mareeba) family, near Mareeba, Queensland, Australia, November

Dave Watts / Mareeba rock wallaby (Petrogale mareeba) portrait, near Mareeba, Queensland, Australia, November

Roland Seitre / Greater bilby (Macrotis lagotis) baby in pouch, vulnerable species, captive, at breeding station, Australia

Roland Seitre / Greater bilby (Macrotis lagotis) two babies, vulnerable species, captive, Adelaide Zoo, South Australia

Roland Seitre / Greater bilby (Macrotis lagotis) female with two babies, vulnerable species, captive, Adelaide Zoo, South Australia

Inaki Relanzon / Koala (Phascolarctos cinereus) with young in tree, Great Otway National Park, Victoria State, Australia.

Inaki Relanzon / Koala (Phascolarctos cinereus) curled up sleeping in tree, Great Otway National Park, Victoria State, Australia.

Pete Oxford / San Lucas marsupial frog (Gastrotheca pseustes) base of Chimborazo Volcano (Highest mountain in Ecuador), Andes, Ecuador, South America - endemic to Ecuador, endangered species.

Bert Willaert / Pair of mating Mouse Opossums (Marmosops cf. noctivagus) hanging from prehensile tail. Ecuador,

Tim Laman / Portrait of Dorcopsis (Dorcopsulus sp.). New species of wallaby from the Foja Mountains discovered by Kris Helgen. Captured near Bog Camp at 1650 m. Papua, Indonesia, 2008. (taken during Conservation...

Dave Watts / Bridled nailtail wallaby (Onychogalea fraenata) Queensland, Australia, Endangered species, October

Konrad Wothe / Lumholtz's Tree-kangaroo (Dendrolagus lumholtzi) sitting on branch in rainforest, Atherton Tablelands, Queensland, Australia, October

Dave Watts / Green ringtail possum (Pseudocheirus archeri) female with baby in pouch, looking down from tree, Queensland, Australia, November

Dave Watts / Eastern grey kangaroo (Macropus giganteus) family group, male, female and large joey, Tasmania, Australia, February

Dave Watts / Eastern grey kangaroo (Macropus giganteus) two males boxing, Australian Capital Territory, Australia, December

Dave Watts / Eastern grey kangaroo (Macropus giganteus) bounding, Australian Capital Territory, Australia, September

Rolf Nussbaumer / Virginia Opossum (Didelphis virginiana) juvenile drinking from wetland lake, Fennessey Ranch, Refugio, Coastal Bend, Texas Coast, USA