The week in wildlife

A brushtailed possum joey opens its mother's pouch to take a peak at the outside world in a veterinary clinic in Sydney, Australia Photograph: Leanne Cooper/guardian.co.uk

A fish is squeezed in the sharp beak of a kingfisher. The brightly coloured bird swooped on the fish after spending minutes watching the water. The fish was devoured in one mouthful Photograph: Ilia Shalamaev/Solent News & Photo Agency

Wolves in a forest in the exclusion zone around the Chernobyl nuclear reactor during a foggy morning near the abandoned village of Borshchevka, which is situated in the radiation ecology reserve. Wildlife in the exclusion zone increased despite the radiation, since people left the area after the 1986 nuclear disaster, keepers of the reserve said Photograph: Vasily Fedosenko/Reuters

Thousands of walrus gather on Alaska's north-west coast. An environmental group is seeking to list the walrus as an endangered or threatened species because of disappearing summer sea ice Photograph: U.S. Fish and Wildlife Service/AP

A villager walks next to a boat trapped in the mass of water hyacinths in the Tha Chin river in Thailand. The mass of hyacinths is blocking the waterway, lowering the river quality and affecting the villagers' daily lives Photograph: Rungroj Yongrit/EPA

A bird sits on top of a blade of grass in a meadow in Hungary at dawn Photograph: Imre Foeldi/guardian.co.uk

A five-week-old dwarf mongoose pup stands next to its parent at the Bronx zoo in New York. A social creature that lives in small groups led by a dominant male and female, the dwarf mongoose is the smallest carnivore in Africa Photograph: Julie Larsen Maher/AP

Heathland lavender with a backdrop of pine trees in the RSPB Farnham Heath nature reserve. The RSPB is clearing the conifer plantation so that the open heathland can be restored Photograph: Graham Turner/Guardian

A celebration of insects and art at London zoo and the Southbank Centre in London hopes to help our ailing friend, the bee. Pestival features insect-inspired music, film, comedy, talks, workshops and installations Photograph: Toby Melville/Reuters

An arctic tern. Seabirds breeding in Scotland have had their most productive year for almost a decade, according to the RSPB Scotland. A 'plentiful supply' of food in the form of sand eels and other small fish seems to have contributed to successes for many species that have struggled to raise chicks in recent years Photograph: RSPB Scotland/PA

Four polar bears fighting over a whale carcass in Svalbard, Norway. Marine mammal experts and the WWF believe the polar bear population in the region is increasing Photograph: Steven Kazlowski/Barcroft Media

The emerald green disc on the tail feather of the king bird of paradise which are used in a courtship ritual. The bird was seen in the extinct Mount Bosavi volcano in Papua New Guinea, where scientists, cavers and wildlife film-makers ventured in search of rare animals and birds Photograph: Ulla Lohmann/guardian.co.uk

A bee collects pollen from tree blossoms on the first day of spring, September in Canberra, Australia. In the UK, spring will arrive a month earlier in 40 years' time thanks to the warming oceans around British Isles, new study predicts Photograph: Mark Kolbe/Getty Images

A family of Pacific brant on the Yukon-Kuskokwim Delta, Alaska. Until recently, nearly the entire population of the small, dark, geese wintered in Mexico, but now as many as to 30% are opting to spend their winters in Alaska instead, according to a US Geological Survey-led study Photograph: Jeff Wasley/U.S. Geological Survey

A bluefin tuna inside a transport cage. The European commission decided to support a ban on the international trade of North Atlantic and Mediterranean bluefin tuna this week Photograph: Gavin Newman/Greenpeace International/EPA

A villager picks up water spinach growing in a polluted pond, which is used as a dumping site for waste from a palm oil factory, in the Luwu district of Indonesia's South Sulawesi province Photograph: Yusuf Ahmad/Reuters

A dead penguin lies on the beach near Turkish bulk carrier MV SELI 1, carrying a 30,000 tonne coal cargo, that ran aground near Cape Town. The carrier, clearly visible from city vantage points, is reportedly carrying 600 tonnes of heavy fuel oil and 60 tonnes of diesel, although no fuel tanks had ruptured, city officials said Photograph: Mike Hutchings/Reuters

An alpaca, a cousin of the llama, enjoys his straw breakfast at Vauxhall City Farm in London Photograph: Katie Collins/PA

Coral from the genera Hydrozoanthus, believed to be new to the Galapagos. A three-year study in the Galapagos led by the University of Southampton has discovered new species of coral and rediscovered species thought exinct in the northern Wolf and Darwin islands Photograph: University of Southampton

A pink grasshopper was discovered in Devon by Daniel Tate, 11. Tate was at the first Minibeasts On The Marshes event in Seaton Marshes when he stumbled upon the creature, which was identified as a young adult meadow grasshopper that was born pink due to a genetic mutation Photograph: East Devon District Council/PA