Rockhopper penguins' athleticism makes them the daredevils of the animal world. Will a warming climate slow them down?

On a rocky ledge over the coast of an island in the far south Atlantic Ocean, a young penguin peers nervously at the chasm ahead. Her bushy yellow eyebrows waggle as she tilts her head one way, then another, scouting the route home to her nest high above. This next step will be a doozy. To reach the ledge on the other side, she’ll have to make a gr...