Animals

Narwhals are arctic whales that live in social groups called pods. CoreyFord/Getty Images hide caption

Bear Michal sleeps on the ground at Bear Sanctuary Müritz in Germany in May 2015. FOUR PAWS/FOUR PAWS hide caption

A Fiji Island iguana is seen at the Smithsonian National Zoological Park in Washington, D.C. A new study suggests these iguanas reached the tropical island by crossing thousands of miles of ocean. The Washington Post/Getty Images hide caption

A still from Latvian film Flow, which won the Oscar for best animated feature earlier this month. Courtesy of Sideshow and Janus Films hide caption

In the Cretaceous period, sauropods were major ecosystem engineers. They knocked down trees and distributed nutrients through their poop, dramatically altering the landscape of ancient Earth. Joe Regan/Getty Images hide caption

A new report finds butterfly populations are declining in the U.S. twomeows/Getty Images/Moment RF hide caption

Conservation detection dogs help biologists find a range of hard-to-find targets, from invasive and endangered species, to animal scat to poachers. Collette Yee hide caption

Left, a regular mouse sits near a genetically modified mouse, seen to the right. The latter has been genetically modified to have the longer, golden hair and fat stores of a woolly mammoth. Colossal Biosciences hide caption

Mice may exhibit revival-like behaviors to help unconscious cage mates. Georgejason/Getty Images/iStockphoto hide caption