A dog in Colombia figured out how to buy cookies with leaves after watching people pay with money.

The dog has been trading leaves for treats at a school cookie stand for years.

The dog lives at Institución Educativa Técnico Diversificado de Monterrey in Monterrey, Colombia, where he's been cared for by faculty since around 2013.

Gladys Barreto, who works at the small campus shop, says the dog comes for cookies every day.

The Day Everything Changed

Teacher Angela Garcia Bernal watched the moment the dog first made the connection.

"One day, spontaneously, he appeared with a leaf in his mouth, wagging his tail and letting it be known that he wanted a cookie," Bernal told The Dodo.

The staff accepted his leafy payment.

An Unofficial Mascot

The dog serves as the school's unofficial mascot, beloved by students, faculty, and staff.

He provides security in exchange for food, shelter, and water.

Students regularly take photos with him and post them on social media.

A System With Rules

The school staff carefully manage the dog's cookie habit.

They limit his daily purchases and only give him dog-safe treats to prevent overindulgence.

"When you first see it, you almost want to cry," Bernal explained. "He's found a way to make himself understood."