Peruna is the official mascot and fight song of the Southern Methodist University (SMU) Mustangs, named after Peruna, a popular patent medicine (18 percent alcohol). The name "Peruna" is given to each successive live mascot. The mascot debuted in 1932, and since then a black Shetland pony, Peruna, has been present at every SMU home football game except for one. The costumed mascot is also referred to as "Peruna." Peruna was selected the #10 Best College Mascot by America's Best and Top Ten in 2009.

On November 4, 1932, Peruna I made his first mascot appearance, appearing at the SMU football game against Texas A&M University. Peruna I was a four-year old, 150-pound pony that was donated by T.E. Jones, the owner of Arlington Downs racetrack. Cy Barcus, a 1929 graduate of Perkins School of Theology and director of the Mustang Band, introduced the black Shetland pony as the mascot and volunteered the name Peruna, which was already the name of the school Fight Song. In the March 22, 1985, edition of The Daily Campus, Barcus related his story to Linda Beheler: “I was out on a picnic and saw a little black horse running through the high weeds and I said, ‘that would make a good mascot for SMU.’ So I went to coach Ray Morrison and said, ‘Ray, I’ve found a horse that I think would make a good mascot,’ and he told me to bring it to the pep meeting. So I got a popular [student] to bring the pony to the pep rally and from then on it became the official school mascot.” On Halloween 1934, Peruna I escaped from his on-campus living quarters and was struck and killed by an automobile on Mockingbird Lane. The event devastated the SMU community and sent the university into mourning.

Since then, the university has moved Peruna's living quarters from campus to a Dallas-area ranch. Nine Perunas have represented SMU's athletic teams. The most recent to be retired was Peruna VIII, in 2011. Peruna VIII represented the school from 1997 until 2011. After he was retired from the field, Peruna VIII continued to represent the school on The Boulevard, the tailgating area for football games for one season while Peruna IX was in training. Peruna IX has represented the school since October 15, 2011.

Following the death of Peruna I, W.E. Culwell (owner of Culwell and Sons) began a tradition of supplying SMU’s mascot. The Culwell family has donated and cared for Peruna II-Peruna IX. According to Culwell’s son, C.W. "Cully" Culwell (’54), “He (Dad) would go to every game and serve barbecue to the players after the game; he really loved the school….Dad donated a Shetland pony because they have a greater longevity than a Quarter Horse.” (Shetlands will normally live 25 years or more, while a Quarter Horse will only live 15–18 years.) His generosity continued until his death in 1964 and has been continued by the Culwell family. Until 1993, the mascot was stabled on the 500-acre (2.0 km²) Culwell Ranch in Grapevine. Since then, the stabling location has been kept a secret. To date, nine mascots have represented SMU...seven stallions and two mares, although hard-core types prefer all-black stallions because of their alleged vitality and spirit. When Cully Culwell was having difficulty locating a black stallion to replace Peruna VI, he shared, “stallions are hard to obtain now because most young male horses are castrated to make them tamer….a stallion which is more aggressive, better represents the spirit of the SMU Mustangs.”

The first football teams at SMU were unofficially known as the "Parsons" because of the large number of theology students on the team, but after SMU won a state championship in women's basketball, it was determined that the university's teams needed an official mascot. Bulls, Rams, Comanches and Rattlers were among the names submitted by members of the student body. The list was narrowed to three finalists, and at a pep assembly on October 17, 1917, the name "Mustangs" was selected over Bisons and Greyhounds. The contributor of the winning symbol was Miss Dorothy Amann, President Hyer's secretary. She was struck by the idea while watching the team practice from her office in Dallas Hall: "Why, out there, on the football field, it looks just like a bunch of wild Mustangs!". The mustang is representative of the fleet-footed animal which is native to Texas.

The name Peruna originated in the fall of 1915 when SMU student George Sexton substituted the words, "She'll be loaded with Peruna when she comes ..." to the tune of "Coming 'Round the Mountain." In the early part of the century, Peruna was the name of the most famous elixir in Texas and had a reputation as a cure-all. The popularity of Peruna soared during Prohibition due to the high alcohol content allowed for "medicinal" purposes. Peruna happens to mean "potato" in Finnish.

The first mascot was a 28” high, 150-pound pony donated by T.E. Jones of Arlington Downs. The feisty miniature black stallion made his first appearance at a pep rally, November 4, 1932. He was promptly named ‘Peruna’ after a popular patent medicine (18 percent alcohol). Legend has it that the medicine was ‘full of kick’, as was SMU's first mascot. He was kept on campus under the care of an organization called “The Saddle Burrs”.

A week before Peruna I's death, he traveled to New York for the Fordham game where a city cab was his mode of travel. At the time, Bob Goodrich (who later became