For all lovers of those tuxedo-colored, flightless birds, today, World Penguin Day, is for you.

According to the Ian Somerhalder Foundation, April 25 got its roots as World Penguin Day on Antarctica, where scientists working at McMurdo research station noticed a remarkable coincidence with a colony of Adelie penguins.

On April 25 of every year, after spending months at sea, the colony would return. It happened like clockwork for seven years in a row, which was enough to prompt the researchers to plan for the penguins' arrival and make a celebration out of their appearance.

There is no clear record of when exactly World Penguin Day began, but celebrations have been traced back to at least 2007.

To celebrate World Penguin Day, the Antarctic Ocean Alliance compiled a list of penguin facts. The full list is here, and below are some highlights.

  • Penguins have the highest feather density of any bird, at about 100 feathers per square inch.
  • Penguins drink saltwater, but their supraorbital gland filters salt from their bloodstream. The salt gets excreted when penguins sneeze.
  • The tuxedo pattern of a penguin's feathers is a form of camouflage. From above, their dark body blends into the ocean water, from below their white stomachs match the bright, sun-lit surface.
  • Penguins spend as much as 75 percent of their lives at sea, coming ashore for molting or breeding.

In honor of World Penguin Day, we've rounded up some enjoyable penguin videos below.