A song written chiefly by John Lennon, "Hey Bulldog" was one of only four previously unreleased songs contributed to the animated feature film Yellow Submarine. The group had little involvement in the project; Lennon himself has treated the song with little importance, "They wanted another song, so I knocked off 'Hey Bulldog.' It's a good-sounding record that means nothing." The rather impromptu manner in which it was recorded supports this statement. The Sunday session was booked on February 11th for the purposes of filming the Beatles at work in the studio as a promotional clip to promote the release of the "Lady Madonna" single, but the group decided to put the studio time to productive use, completing the entire recording in a single ten-hour session. Footage of the session has recently resurfaced and has been synched to the finished "Hey Bulldog" recording, resulting in a kind of unintentional music video.
Despite all the throwaway track disclaimers, the actual song is a strong one, even rivaling Paul McCartney's "Lady Madonna" as an A-side single. The music is centered around a bluesy, noir-ish riff, starting with low piano notes, repeated with fuzz guitar and copied on bass, Ringo Starr joining in with a thudding tom fill intro. The verse has a kind of mid-tempo pulsing rhythm supported by churning piano from Lennon. McCartney displays his fluid bass playing, a steady flow of plunking notes emanating from his dampened strings. Lennon vocals are double tracked as he delivers the song's vaguely caustic lyrics in short punctuated phrases, "Sheepdog, standing in the rain/Bullfrog, doin' it again/Some kind of happiness is measured out in miles/What makes you think you're something special when you smile?" The chorus takes on a brighter tone, the chords rising in an ascending progression, Lennon offering a consoling ear, urging, "You can talk to me/You can talk to me/If you're lonely you can talk to me." The song finishes on a vamp on the opening riff, Lennon repeating the title "Hey Bulldog." The song has a curious ending, McCartney joining Lennon in the vocal booth for some light-hearted barking and howling, a common ad-lib practice when a song had reached the expected fade-out point; this time the group deciding to leave in the extraneous material.
Sadly the "Hey Bulldog" sequence was edited out of most early copies of the Yellow Submarine film, but has since been restored to the re-release of the film in 2000.