A man rides his bicycle as a wave crashes at La Libertad malecon on May 13, 2015. El Salvador emergency authorities has declared an orange alert along the Pacific coast due to a large swell that affected the Salvadoran coast. The swell originated from the extra-tropical storms that formed in New Zealand and the Southern hemisphere, according to El Salvador's Ministry of Environment and Natural Resources. (Photo by Jose Cabezas/Reuters)

“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

Despite their thick fur, this group of dogs and puppies in China feel the cold. Luckily, in the winter, they're allowed to huddle round a staff canteen stove in their home in Jiulongjiang Forest Park, Rucheng County.

The golden monkey (Cercopithecus kandti) is a species of Old World monkey found in the Virunga volcanic mountains of Central Africa, including four national parks: Mgahinga, in south-west Uganda; Volcanoes, in north-west Rwanda; and Virunga and Kahuzi-Biéga, in the eastern Democratic Republic of Congo. It is restricted to highland forest, especially near bamboo.

The Atlantic Puffin is definitely a curious-looking bird. The special coloring that this bird develops for the breeding season in the spring is very reminiscent of tropical birds. The bright colors of the beak and the markings around the eyes serve no particular advantage and have evolved as a result of sexual selection. However, Puffins don’t look that pretty all year round. They shed all these festive colors in partial moult after the breeding season is over. They lose the ornaments around their eyes, their face becomes darker, and their beak becomes very different. The natural habitat of these birds is the cold waters of the North Atlantic Ocean.

Migingo is a tiny 2,000-square-metre (0.49-acre; 0.20-hectare) island, about half the size of a football pitch, in Lake Victoria. Migingo is a tiny rock island, less than half-an-acre or about half the size of a football field, located in Lake Victoria, the largest lake in Africa and the largest tropical lake in the world. Although tiny in size, the island is home to 131 people (according to 2009 census) living in crammed huts made of corrugated sheets and wood. Despite shabby living conditions, Migingo Island boasts of five bars, a beauty salon, a pharmacy as well as several hotels and numerous brothels.

Gunung Leuser National Park is a national park covering 7,927 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after Mount Leuser (3,381 m), protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside the park. Together with Bukit Barisan Selatan and Kerinci Seblat national parks it forms a World Heritage Site, Tropical Rainforest Heritage of Sumatra.

A person tries to extinguish flames as sparks fly during a wild forest fire in Valparaiso, Chile, Sunday April 13, 2014. Authorities say the fires have destroyed hundreds of homes, forced the evacuation of thousands and claimed the lives of at least seven people. (Photo by Luis Hidalgo/AP Photo)