The week in wildlife – in pictures

A brown capuchin monkey holds a fruit in the Botanic Garden of Rio de Janeiro, Brazil Photograph: Pablo Porciuncula/AFP/Getty Images

A dragonfly with red wings in the West Bank village of Wadi Fukin Photograph: Abed Al Hashlamoun/EPA

A young sea lion pup which has rolled in the sand in San Cristobal, Galapagos Islands, to protect it from the hot sun Photograph: Michal Tyl/Barcroft Media

An Indian cobra hatchling emerges from an egg on the outskirts of Bhubaneswar. The Indian cobra is a venomous snake indigenous to South Asia, found across India, Pakistan, Bangladesh and Sri Lanka Photograph: Asit Kumar/AFP/Getty Images

Catfish washed ashore in polluted waters of Manila bay, Philippines. A large number of fish appeared in the shallow waters of Manila Bay shortly after the tropical storm Rumbia hit the capital Photograph: Dennis M Sabangan/EPA

Female nyalas at the Singapore zoo. Nyalas are a spiral-horned antelope native to southern Africa Photograph: Suhaimi Abdullah/Getty Images

Egret chicks wait in a nest for their parents to return with food in the Panbazar area on the banks of the Brahmaputra River in Guwahati city, India Photograph: EPA

Jai, a tiger at the Phoenix zoo, breaks apart frozen trout while sitting in his pool to keep cool Photograph: Matt York/AP

Pacific krill. Millions of the inch-long shrimp-like animals have been washing up on beaches between Eureka, California and Newport, Oregon. Scientists do not know the reason why. Strong winds may have pushed them ashore while they were mating near the surface, or they may have run into an area of low oxygen Photograph: Jaime Gomez Gutierrez/AP

Two cranes in a field of wildflowers near Petersdorf, Germany Photograph: Patrick Pleul/dpa

A group of scalloped hammerhead sharks swim off Cocos Island, Costa Rica. Their numbers have been diminished by overfishing Photograph: Franco Banfi/Barcroft Media

A large blue butterfly, one of the greatest British wildlife success stories of the past 30 years. The first large blue butterflies of the year have been spotted at Collard Hill, Somerset Photograph: National Trust/PA

Two juvenile siskins fighting in Northumberland Photograph: Will Nicholls/Rex Features

A duck searches for food at a beach covered by a thick layer of green algae in Qingdao, China. A large quantity of non-poisonous green seaweed, enteromorpha prolifera, hit the Qingdao coast Photograph: ChinaFotoPress via Getty Images

Years of drought are causing water levels at Agua Caliente in Tucson, Arizona to drop to extremely low levels. The main lake, as well as another overflow, are fed by a natural spring, seasonal rains and snowmelt runoff from the nearby Rincon Mountains.55,000 gallons of water each day are pumped into the lake Photograph: Will Seberger/ZUMA Press/Corbis

Scientists have been studying a type of antibiotic that is produced by bacteria that live in symbiosis with leaf cutter ants. They have identified the genetic pathway involved in producing the antibiotic, opening the possibility to use this natural product as the basis for new drugs, including anti-cancer treatments Photograph: Gail Shumway/Getty Images

One of the 10 zebra-snouted seahorses, with its father, born at the National Sea Life Centre in Birmingham. Zebra-snouted seahorses come from the Philippines and are one of the species under threat from the Chinese traditional medicine trade Photograph: National Sea Life Centre/PA

Paddy the wombat is 27, which makes him the oldest of his kind on record at the Ballarat wildlife park, Victoria, Australia Photograph: Jay Town/Newspix/Rex Features