Listen to I Guess That's Why They Call It the Blues (From "Peter's Friends") online. I Guess That's Why They Call It the Blues (From "Peter's Friends") is an English language song and is sung by Sax Project. I Guess That's Why They Call It the Blues (From "Peter's Friends"), from the album Saxo and Movies Vol. 3, was released in the year 2011. The duration of the song is 3:05. Download English songs online from JioSaavn.