A history enthusiast, dressed as a soldier, marches before the re-enactment of Napoleon's famous battle of Austerlitz near the southern Moravian town of Slavkov u Brna, Czech Republic December 3, 2016. (Photo by David W. Cerny/Reuters)

Bjorn, aged 5, smiles as he poses with a Owl butterfly during an event to launch the Sensational Butterflies exhibition at the Natural History Museum in London, Britain March 23, 2016. The exhibition opens to the public on March 24 and runs until September 11. (Photo by Dylan Martinez/Reuters)

Murad Khydyrov, horse and monkey trainer at the Great Moscow State Circus, and chimpanzee named Micky get ready for a rehearsal of the show called “History” as the circus prepares for its new season, which is to begin on September 19, in Moscow on September 17, 2020. (Photo by Natalia Kolesnikova/AFP Photo)

A policeman stops a cyclist as demonstrators from Extinction Rebellion (XR) protest during the NATO Summit by blocking the A12 highway in The Hague, The Netherlands, 25 June 2025. The Netherlands, for the first time in NATO's history of existence, is hosting a NATO summit. (Photo by Sebastiaan Barel/EPA)

A historical re-enactor poses for a photograph in a living history camp as he prepares to take part in an anniversary event for the Battle of Bosworth near Market Bosworth in central Britain August 22, 2015. The Battle of Bosworth took place in 1485 during the War of the Roses between the Houses of Lancaster and the House of York. King Richard III was defeated by Henry Tudor marking the end of Plantagenet rule and the beginning of the Tudor dynasty. (Photo by Neil Hall/Reuters)

A woman takes a selfie with “RoboThespian” at Robots, a major new exhibition at Science Museum in London, England on February 7, 2017. Exhibition showcases 500-year history of robots, with over 100 robots and the largest collection of humanoid robots ever displayed. (Photo by Tolga Akmen/Anadolu Agency/Getty Images)

“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)