Last night was a great one to be at the Minnesota zoo. Gov’t Mule—a side-project of Allman Brothers guitarist Warren Haynes—was playing, the air temperature was perfect, humidity was low, and even the caribou were in a friskier-than-usual mood.

Since forming in 1994, Gov’t Mule has become a staple of the festival/jam-band circuit. And, by virtue of his position as keeper of the sacred Allman Brothers sound and his other part-time gig filling in for Jerry Garcia whenever the surviving members of the Grateful Dead decide to put on a show, guitarist Warren Haynes has emerged as the elder statesman of the Gibson electric flame-top.

In addition to keeping the legacy of two of rock 'n’ roll’s most venerable franchises alive, Haynes, in Gov’t Mule, has appointed himself keeper of the flame for almost every great rock guitarist of the 20th century. Duane, Jerry, Jimi Hendrix, Jimmy Page, Keith Richards, Jeff Beck, Stevie Ray—you name it, he’s studied them. The man seemingly has an entire encyclopedia of rock ‘n’ roll stored in his fingers, and a blade-server of a brain that gives him access to it all, at any given moment. Standing up there with his graying red hair, pot belly, and craggy face, he looks like a mad professor of rock, and his concerts are like extemporaneous aural lectures on the history of electric guitar.

Indeed, Gov’t Mule is the sort of band you could see 10 days in a row and never hear the same song twice. (Check out their set lists from the past two weeks, including last night's, if you don’t believe me.) Last night, along with some Mule originals, Haynes dug deep into the vault to pull out a couple of Beatles tunes (“Tomorrow Never Knows” and “She Said, She Said”), Jimi Hendrix’s “If 6 was 9,” a few riff references to Steppenwolf, Badfinger, and Black Sabbath, and—for local flavor—a cover of Prince’s “When Doves Cry,” which he dovetailed into one of his own tunes, “Beautifully Broken,” then back into “Doves.” Haynes doesn’t look like the kind of person who knows or cares what a crying dove sounds like, unless he happens to have shot one, but he gave the song everything he could, including one of countless blistering solos.

Gov’t Mule is also one of those bands that has a third and fourth gear they can kick into at will, which they did in the second set with a muscular version of Led Zeppelin’s “Trampled Underfoot,” followed by a little Stones teaser from “Gimme Shelter,” into a long jam on the pulsing signature riff of the Dead’s “The Other One.” For the seniors in the crowd, he pulled out Humble Pie’s “Thirty Days in the Hole,” and ended playing an acoustic guitar on a punchy, feel-good rendering of Van Morrison’s “Into the Mystic.”

All in all, professor Haynes delivered an inspired lecture, in the best musical classroom around—the zoo’s Weesner Amphitheatre. If caribou could clap, I’m sure they would’ve.