When Def Leppard released their single “Animal” on July 20, 1987, it was the herald of a new age for the band and rock 'n' roll in general. It was the first single from Hysteria, the behemoth album that would go on to change everything.

The LP was made amid a world of turmoil, characterized by the car wreck that left drummer Rick Allen without an arm. The British band had started work on Hysteria in 1984, with “Animal” one of the first tracks to approach completion. But in the three years of stop-go production, the song went through a complete metamorphosis. It was the final song Allen contributed to before his accident, and the backing track that included his acoustic drumming remained until the band recorded another version using a drum machine, while the drummer re-learned to play using a partly electronic kit.

That was done in Ireland, but when production moved to France in 1985 for a new stage of development, singer Joe Elliott laid down a new vocal track.

“The one thing about that song, as opposed to everything else on the album [is that] I sang the lead vocal to a completely different backing track,” Elliott told Classic Rock in 2014. “It was vastly different. We went to work in Paris; I remember we were there when Live Aid was on, we were there for Bastille Day and we worked in this little studio.

“I did the vocal, [then] we spent a couple of days experimenting with it and nailing it down. And then when we took the tapes back to Holland, where we went to finish the album off. … We kind of grew tired of the backing track, but everybody was commenting on how much they liked the lead vocal.”

He remembered producer Mutt Lange – recruited after two failed attempts to make the record without him – weighing in by saying, "What I’m gonna do is, I’m gonna strip all the track off and just leave the vocal playing against the drums." He told the rest of the band: "I want you guys to just play underneath and see what you come up with." "We totally updated the song to the point where it’s almost timeless now, whereas before it was starting to age even before it was released," Elliott noted.

Guitarist Phil Collen recalled the development of “Animal” from the rough demo he started with. "It was something that was OK, and … going back to Mutt Lange, the genius of him, he said, ‘Yeah, this is OK but this can be great,'" he told Songfacts. "That’s always his thing. ‘Yeah, it can be all right and it can be an OK song, but we want to make it great.’ And I think we achieved that. Certainly with the album Hysteria. It had a different kind of response to it than if we had just sat there and released the first draft.”

Def Leppard shot "Animal"'s promotional video in a real-life circus, to draw a comparison between the animals’ life on the road and the band’s. “We were living with these people in a traveling circus for just a couple of days,” bassist Rick Savage recalled. “We wanted to try and capture the seedier side of it rather than the glamor and the performance side … getting involved with the mucking out of the animals … the old caravans and the straw in the back of the hut and things.”

Watch Def Leppard’s 'Animal' Video

The band had already secured a respectable reputation in the U.S. with the 1983 album Pyromania, but the release of “Women” as the first Hysteria single in the States failed to offer the kind of upward leap they’d been hoping for. “Animal” came first in the U.K. and it was their first Top 10 hit at home; its Stateside release in September went to the Top 20 and reached No. 5 on the Mainstream Rock chart. That helped draw attention to Hysteria, which needed to sell 12 million copies to meet the record label’s expectations. It eventually exceeded them.

Def Leppard said “Animal” was the most difficult song to complete for the album, with producer Lange’s approach involving a painstaking layer-by-layer construction while maintaining a distance between each instrument. "The guitars were a little bit like the Police, and the song had this Frankie Goes to Hollywood vibe to it, but on top of that it was a rock song," Collen later reflected. "It was our first hit in England, so that is quite special as well."

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