According to Adrian Bromley of Chronicles of Chaos, Sounds of the Animal Kingdom is "intense and brutal [...] meld[ing] grindcore, death metal and hardcore attributes into one pounding rhythm".

[7] The Japanese release features three more cover songs as bonus tracks; "Hippie Cult" by Agathocles, "Cybergod" by Nausea and "Cornucopia" by Black Sabbath.

[7][10] According to Hoak, the band would write and jam material at their rehearsal before handing "rough tracks" to vocalist Kevin Sharp, whom would fit or make up lyrics for the music.

[7] Bassist Dan Lilker felt that the album's production was "a tiny bit muffled, and that’s probably due to the fact that we were just smoking so much weed and saying, 'Yeah, man, sounds killer.'

[7] The liner notes features a quote from The Naked Ape (1967) by English zoologist and ethologist Desmond Morris, which Hoak found in a library whilst brainstorming ideas for its cover.

[7] Some journalists described the lyrics as based on The Naked Ape and/or Morris' ideas,[14][15] which Hoak denied, stating that the title had already been decided before he and Sharp realised the similarites between the album's themes and the book and discussed its concept.

[7] The album's cover artwork features a photoshopped image that merges a stock photo of a gorilla with the UPS driver to Relapse Records,[7] whom the art director paid with a case of beer.

[20] Brutal Truth reunited in May 2006;[9] in October of that year, Relapse reissused the album and Kill Trend Suicide together in a remastered package by Scott Hull of Pig Destroyer.

[21] Mike DaRonco of AllMusic praised Sounds of the Animal Kingdom as "more structured and compounded than Cannibal Corpse will ever be", and its "grim but realistic perspective on our eventual apocalypse" compared to death metal's typical subject matters.

[14] Bromley found the album "very creative at times" and deemed it superior to Kill Trend Suicide, but also considered it "lacking [in] some of the momentum and craziness" of Need to Control (1994).

"[25] In their reviews of the 2006 reissue with Kill Trend Suicide, André Bohnensack of Ox-Fanzine described Sounds of the Animal Kingdom as the band's peak and a perfection of its "combination of rough grindcore and all kinds of sound experiments",[27] whilst Metal Injection called it a culmination of "the epic scope of [Extreme Conditions Demand Extreme Responses], the experimentation of [Need to Control], and the raw fury of [Kill Trend Suicide]".