When a male gentoo penguin "falls in love" with a female penguin, he searches the entire beach to find the perfect pebble to present to her.
25
Cymothoa exigua is a type of parasite that enters through fish's gills, eats their tongue, and then replaces it.
6
Alligator snapping turtles can live for over 150 years. Scientists know this because some of the turtles had musket balls in their stomachs.
271
Domestic pigs average a top speed of about 11 miles per hour.
182
Sharks, like other fish, have their reproductive organs in their chests.
248
Cats and dogs can hear ultrasound.
350