“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)

A girl performs martial arts during a function to mark International Women's Day at a school in Hyderabad, India, on March 7, 2014. (Photo by Mahesh Kumar A./Associated Press)

An unidentified runner gestures while being attended by medical services following the first running of the bulls of the San Fermin festival in Pamplona, northern Spain, July 7, 2015. Two runners were gored in the run that lasted 2 minutes and 23 seconds, according to local media. (Photo by Eloy Alonso/Reuters)

Elephants spray tourists with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, about 80 km (50 miles) north of Bangkok, April 9, 2014. (Photo by Rungroj Yongrit/EFE)

People in costume take photos during a Halloween event on October 31, 2015 in Lan Kwai Fong, Central District, Hong Kong. Halloween, a named taken from 'All Hallows' Even' falls on the day before All Saints' Day on November 1, a holiday when Christians remember their deceased loved ones. (Photo by Jerome Favre/Getty Images)

A couple ride a motorcycle along a street during snow in Altay, Xinjiang Uighur Autonomous Region, China, November 8, 2015. Picture taken November 8, 2015. (Photo by Reuters/Stringer)

A woman crowd-surfs in front of the main stage at the Woodstock Festival in Kostrzyn-upon-Odra, close to the Polish-German border, August 2, 2014. Some 500 thousand people attended the festival that is the brainchild of Polish journalist and social campaigner Jerzy Owsiak. He initiated the event to say thank you to those who donated money to his GOCC charity organisation that delivers medical care for children. (Photo by Thomas Peter/Reuters)

Local men help a wounded woman after a mortar attack by the Ukrainian army of the center of Donetsk, Ukraine, 14 August 2014. Reports state that ten local people where wounded and one killed after the mortar attack. (Photo by Sergei Ilnitsky/EPA)