Happy Feet: A Gallery of Pudgy Penguins - Gentoo penguin [LiveScience 2012-02-27]
Penguin Pomp: Birds of a Feather
Credit: Todd Stailey, Tennessee Aquarium
A flock of gentoo penguins at the Tennessee Aquarium in Chattanooga puts on a show. At heights of almost 3 feet (1 meter), gentoos are the third-largest penguin species in the world. Gentoos build nests out of round, smooth stones, which are highly prized by females. To curry favor with a potential mate, male gentoos sometimes present "gifts" of these coveted rocks.