World Rat Day was founded by an Internet mailing list in 2002

April 4 (UPI) -- World Rat Day, celebrated annually on April 4, began with an online news group in 2002 as a means to celebrating pet rats around the globe.

The holiday was first celebrated in 2002, when members of the Ratlist, an online mailing group for owners of pet rats and other appreciators of the species, discussed the possibility of an annual day to celebrate the intelligent rodents.

The group members chose April 4, the day of the mailing list's founding, for World Rat Day.

The holiday is celebrated internationally today, with groups dedicated to pet rats holding meet and greet events around the world.

Other holidays and observations for April 4 include Hug a Newsperson Day, International Carrot Day, Jeep 4x4 Day, 404 Day, Vitamin C Day and National Cordon Bleu Day.