Melbourne ‘experimental’ band Dorsal Fins starts the evening with bright lyrics, animal prints and infectious bouncing.

With a total number of band members rivalling that of main act The Cat Empire, the modest stage seems to spill over with their enthusiasm. Frontman duties are equally shared and they showcase an eclectic collection of instruments and twitchy tempos. The scintillating vocals of Ella Thompson (The Bamboos, Axolotl) – carried on clouds of electronic-synth beats and sparkly keys – are a winner, especially in Mind Renovation and Monday Tuesday. Band founder Liam McGorry (Saskwatch/Eagle & the Worm) has assembled a highly talented team of musicians to challenge the usual genre-labelling conventions. Dorsal Fins may still be finding their feet in the development lab and sound studios but their early results prove they are definitely worth keeping close tabs on.

Felix Riebl and Harry James Angus, ubiquitous frontmen and mascots of The Cat Empire, appear laid-back but prepared for a night of revelry as they take to the stage. Grandparents and toddlers sporting cardboard crowns cheer exuberantly. The eight-strong team kick off with Better Than Gold and the disco-infused Prophets In The Sky, featuring an extended scratchy turntable bridge by DJ Jumps. Mesmerising and irresistible, the feverish build up works a treat and the crowd leaps to its feet as soon as Angus starts up the victorious trumpet opening to How To Explain.

Wild Animals and Steal The Light play to the band’s activist concerns, as does The Wine Song – ‘a tribute to all the refugees who brought their music here’. “Whatever your stance is, there is no denying that refugees and asylum seekers are treated very, very badly here,” Angus says in a rare mid-set comment, urging the audience to join the band in supporting the Asylum Seeker Resource Centre.

Dry ice and blazing multicoloured spotlights add to the illusion that we’re at a sold-out concert elsewhere, not surrounded by snow leopards and African grey parrots trying to get some shut-eye. Thankfully, a large screen beside the stage provides reasonable viewing to latecomers who have to contend with spreading their rugs on the mulch.

“How expensive is your picnic blanket? We want some circles!” Riebl encourages before launching into the ever popular In My Pocket. Not a square inch of lawn can be seen by the time the band encores with Hello.

Perhaps it’s the open-air setting but Riebl’s vocals are sorely tested at several points during the evening. It’s a chronic glitch with all their gigs, but it’s abundantly obvious that their audience don’t come for the lyrics.

The Zoo Twilights 2015 program couldn’t have gone out with a bigger bang than with these frisky felines. “We are just in the middle of recording out next album – we really wish we could play you some new stuff tonight. But watch this space!” We shall.