The Sniffer is really weird
[Sniffer Lore Speculation]
I was randomly thinking about the Sniffer for whatever reason and it dawned on me just how weird they are.
Design wise and their in game 'lore'. The thing that got the gears in my head turning are their legs. Unlike every other passive mob in the game, sniffers have 6 legs. Every other standard terrestrial mob has 2-4 legs (cows, pigs, llamas, etc) with the only real exceptions being insects (spiders and bees), and mobs that fly or swim (squids, phantoms, guardians etc.)
It also lays eggs, which if it's a mammal, makes it the only monotreme in Minecraft, which is neat, but still very weird. Now beyond the oddity of being a monotreme (which isn't too insane considering we know the Sniffer is meant to be an ancient mob, thus is probably from early into mammalian evolution), the real weird thing is that their eggs are still good? Like they're able to hatch? And like-
They're on a pottery sherd??? which means they co-existed with one of the ancient civilizations?? Which is WILD because that has several potential implications.
IMPLICATION 1. The sniffers genuinely did just live with the ancient civilization and were pretty standard farm animals for them.
IMPLICATION 2. They PREDATE the ancients and were brought back BY them in the same way the player brings them back, which is why they're on the sherd. Personally, I think this option is FAR more interesting because it aligns with what we see with the rest of the sherds. The number of mobs on the sherds is incredibly limited as they only contain mobs with a notable connection to the ancients, which means the sniffer's existence was NOTABLE to them.
The mobs shown by sherds are;
Breezes (Assumably created by the ancients, being a construct mob only found in the trial chambers.)
Skeletons (Not sure if we should count this as the mob itself because people still have skeletons, it could be standard death iconography.)
'The Mourner' (Warden seems most likely though it's not 1-1. The warden would be incredibly notable to preserve.)
Wolves (Nest friend, makes sense they get a mention)
Everything here is notable enough to be preserved. If they had discovered a literal ancient mob pre-dating them, that would be notable enough to mention. So I think the sniffer pre-dates the ancient civilization (or civilizations, hard to say if it was one giant civilization or a bunch of disconnected ones throughout time but I'm NOT getting into that here.).
Another thing that backs this theory up is the six legs. It's INCREDIBLY weird for a Mammal to have 6 legs, this is because all mammals evolved from the same original 4-legged ancestor. This means Sniffers are from an entirely separate evolutionary branch of land-dwelling animals that went extinct. Which is fucking CRAZY RIGHT??? The fact there was an entirely separate evolutionary tree in minecraft's past is completely fucking nuts like that is such a mind boggling implication to throw into the game. Them being from another evolutionary tree also explains their oddities such as their weird yellow-faces that resemble beaks (but clearly aren't due to how elastic they are) and their aforementioned 6 legs + egg laying.
So, next question, Whats up with the green?
The sniffer has nothing textured beneath it's green layer, and there is nothing else shown in game that could refer to what's beneath it. Additionally due to it's green facial markings, I believe it's safe to conclude the green is apart of the sniffer. So what is it?
My initial thought was; ''Maybe it's moss.' something along the lines of a sloth, essentially. It does align, sniffers are slow and docile, they'd be able to grow something like moss or algae. I think this is a very valid possibility. But the main thing that sways me from this line is thought is the egg.
The egg is also green. Eggs usually have their markings for;
1. Camouflage, a brown egg in a brown environment is harder to find and thus eat.
2. Distinction, the more complex an egg is, the harder it is to mimic and thus makes it harder for other species to replace with their own.
3. Structural integrity, sometimes markings just make the egg sturdier.
I believe the main reason the eggs look like this is camouflage, and the main reason for this is the sniffer's green back and, well, stick with me here; Podzol.
Sniffers are a rather weird red-color. With other mobs we know their colors are like that due to real world influence, (ex. pigs are as pink as they are because of human influence despite it not being good camouflage, but pigs don't have a predator in Minecraft so they don't need it regardless.) but with sniffers the red is weird. I think it's there to blend into their natural environment. It's clear the sniffer has undergone little to no evolutionary changes since it's original environment vanished, so I think originally, Sniffers were from an area with Podzol comprised of brush materials from the biome, which gave it a more reddish-tint than it's brown/green from spruce adjacent biomes.
See, Sniffers having green only on their tops reminds me of aquatic camouflage. In the ocean certain animals have darker tops and lighter bottoms because the sun makes water lighter while looking up and darker while looking down. I think the sniffer's green backs are a means to camouflage with the foliage of their original environment.
Their diet is comprised entirely of seeds, and due to their VERY large size and slow speed, we can assume this does not give them much energy. They spend a lot of their time just loafing around, they even have a dedicated sitting animation. I think they were originally a large herbivorous prey species, with their main predators being avian. Green backs would let them blend into the foliage and reduce the chances of them getting snatched up (Also these birds would have to be ridiculously huge to carry off a sniffer oh my god can you imagine, that's terrifying). Their eggs are colored this way for the same reason, they're much harder to spot if they blend into the ground and the foliage.
Alright time to wrap this together.
The sniffers are an ancient herbivorous prey species. They originally fed on loose foliage to get at their seeds and nuts. Their 'beaks'(?) were used similarly to a birds, being able to crack open a seed's shell to eat the innards. They primarily fed on torch flowers but were not limited to them (But are now, due to their stomachs being specialized for ancient plants, not modern ones).
They likely lived in foliage dense zones with a cooler ambient temperature due to their thick fur (something like a taiga biome with entirely different foliage). They had some natural predators, though they could deal with most terrestrial predators due to their large size. Their main predators were massive flying creatures which could swoop down and pick sniffers off one by one. They evolved their green backs to camouflage against these mobs.
But we know their fate in these ancients times. Sniffers and every other mob from this period went extinct. Some evolved into the mobs we have now, but the sniffer's entire evolutionary branch of the tree is gone, so far as we know.
An unknown amount of time passes and a sniffer egg is discovered by an ancient civilizations. They find a new home in this new age, one without a natural predator. But they could not get their footing as a species due to their stomachs being poorly adapted to newly evolved foliage. Eventually, they would go extinct again, but this time remembered, and more properly preserved.
Now in modern day they've been found again by the player and brought back, likely to repeat the same cycle yet again.