“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 Tengger tribesman prays at Mount Bromo during the annual Kasada ceremony in East Java on August 12, 2014. The Kasada ceremony is a festival held every 14th day of the Kasada month in the traditional Hindu lunar calender to honour Sang Hyang Widhi (God Almighty) and is based on the legend of Roro Anteng and Joko Seger from the Majapahit Kingdom, from which their Tengger tribe name originates. Hundreds of worshippers from the Tengger tribe offer food and livestock as a symbolic sacrifice which they throw into the crater for the blessings of safety and prosperity to their familyies and community. (Photo by Juni Kriswanto/AFP Photo)

Thomas Thwaites of the United Kingdom accepts the 2016 Ig Nobel Prize in Biology for “creating prosthetic extensions of his limbs that allowed him to move in the manner of, and spend time roaming the hills in the company of, goats” during the 26th First Annual Ig Nobel Prize ceremony at Harvard University in Cambridge, Massachusetts, U.S. September 22, 2016. (Photo by Brian Snyder/Reuters)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

Rays from the rising sun shine through the foliage of trees as fog covers the ground near the Guckler Karoly Observatory in Budapest, Hungary, 02 January 2017. (Photo by Balazs Mohai/EPA)

In this photograph taken on February 18, 2016, Pakistani children ride on swings in the predominantly Pashtun Korangi District of Karachi. In a rundown district of Karachi, Rabia balks at a neighbour's proposal to vaccinate her children, demonstrating one of the biggest hurdles to eradicating polio in Pakistan by the end of the year: confused and frightened parents. (Photo by Asif Hassan/AFP Photo)

A herd of wildebeest cross the skyline against the fading light in Masai Mara, Kenya, 25 August 2017. Stunning sunset photos silhouette Africa’s wildlife against streaks of orange and red sky. In August, German photographer Ingo Gerlach was on safari in the Masai Mara when he convinced his safari guide to stop and take in the sunset. The wildlife photographer was rewarded with his patience by an eye-catching sunset, which cast Africa’s wildlife into dark shadows against the vibrant skies. (Photo by Ingo Gerlach/Barcroft Images)

A so-called “Supermoon” dominates the sky while traffic rolls in the streets in Naypyitaw, Myanmar, 03 December 2017. According to the National Aeronautics and Space Administration (NASA) a series of three “Supermoons” – dubbed the “Supermoon trilogy” – will appear in the sky on 03 December 2017, on 01 January 2018 and and 31 January 2018. A “Supermoon” commonly is a full moon at its closest distance to the earth with the moon appearing larger than usual. (Photo by Hein Htet/EPA/EFE)