“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 Nepalese man sits outside a Hindu temple as a goat rests on a parked scooter in Khokana, Lalitpur District, Nepal, Monday, September 26, 2016. Writing on the wall offers prayers to Hindu god Shiva. (Photo by Niranjan Shrestha/AP Photo)

Juno, a Beluga whale, greets a young viewer at the Mystic aquarium in Connecticut, USA on December 5, 2015. (Photo by Tim Clayton/Corbis)

Throughout the course of the long war in Afghanistan, Coalition troops have relied on thousands of military working dogs to help keep them safe, and make their jobs easier. The dogs are trained to detect explosives, to find illegal drugs, to search for missing comrades, or target enemy combatants. Not only are they active on the front lines, but behind the lines they serve as therapy dogs, service dogs, and loyal companions. They also share the same risks as the ground troops, suffering injuries and sometimes death on the battlefields. Gathered here are images of these dogs and their handlers in Afghanistan and back home, from over the past several years, part of the ongoing series here on Afghanistan.

Runners gather at the start line for the annual “Santa Speedo Run”, a charity race through the streets of the Back Bay neighborhood of Boston. (Photo by Gretchen Ertl/Reuters)

Early morning shark Sean McKeon pictured during severe flooding Oliver Plunkett street, Cork city, on February 3, 2014. (Photo by Daragh McSweeney/Provision)

A man takes a picture of models as they pose next to Cosmis Racing Wheels products during the 2016 Moscow International Auto Salon in Moscow, Russia, August 26, 2016. (Photo by Sergei Karpukhin/Reuters)