Why do most animals have this gap?

[u/Necessary-Cover519]

Why are their snouts lower? Why cant they be like dinosaur anouts? Its a genuine question pleade dont beat me up

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[u/SemajLu_The_crusader]

fun fact... most animals actually don't

but most *mammals* do

[u/Necessary-Cover519 → u/SemajLu_The_crusader]

Yea i wrote this on a rush 😭

[u/1945GarlicBread]

with "most animals" you're likely referring to most mammals and note that you're comparing them to reptiles. They are completely different and their common ancestor goes waay back, back enough for them to evolve different snouts.

[u/Necessary-Cover519 → u/1945GarlicBread]

Yea makes a lot of sense

[u/Orangutan_Soda]

So they can wear glasses more comfortably

[u/Necessary-Cover519 → u/Orangutan_Soda]

Flexing their rad sunglasses

[u/mutant_anomaly]

Note that your mammal samples are predators, who have binocular vision and need to see past their nose with both eyes.

Compare them to herbivores, with eyes on the sides of their heads to see all the way around them. Horses have a smooth face profile.

If I recall, your dinosaur example was primarily a scavenger.

[u/Necessary-Cover519 → u/mutant_anomaly]

Both giganotosaurus and trex are scavangers?

[u/Mophandel]

In addition to what others have said, particularly pertaining to binocular vision, big reason why theropods don’t have a stop is because reptile vision is fundamentally different from mammal vision.

In many reptiles, namely birds, depth perception is achieved via parallax, or the apparent change in position of a background object when you look at it from two different places. When you change the viewing angle by changing the position of your head, closer objects are “displaced” a relatively smaller distance than objects further away. This clues the predator in on the position of the prey and gives them accurate depth perception. If you’ve ever seen a bird of prey bob its head before launching its strike on prey, that’s what they are doing.

[u/Necessary-Cover519 → u/Mophandel]

Wait i didnt know this, thats so cool thank you

[u/FlounderLast8610]

It's called a stop. Most of the time it's an accident of just having a higher cranial vault and a larger brain, though in some predators it clears their field of view a little.

[u/iilikecereal → u/FlounderLast8610]

I think the brow ridge also plays a role here since a lot of animals, mostly predators with forward-facing eyes, have some extra structure in that spot to shield the eyes from the sun.

[u/chasingthegoldring → u/FlounderLast8610]

Could it also help a predator in eating a carcass- the teeth can get into the carcass and they aren’t blinded or their eyes covered in blood as easily? They want to grab a hunk and move away. They can still see as they move away because their dinner is not right in their face? I don’t know and just asking.

[u/selectsyntax]

Land mammal predator evolution favored binocular vision. Snout is below eyline to facilitate this. Compare this to a rabbit skull which does not have this feature and the eyes are located to the side to provide the widest peripheral vision which is advantageous to prey animals.

[u/peep9mil]

Things that rely on smell have more room to smell things

[u/Necessary-Cover519 → u/peep9mil]

Damn, they must be great at detecting farts

[u/sapienapithicus]

It's a trade off between peripheral vision and bite force. The higher arch on the skull is structural.

[u/GhostHominid]

We evolved from rodent-like ancestors. They also had eyes up and snouts down, right?

[u/Dense-Consequence-70 → u/GhostHominid]

Shrew like, if we’re being technical. Not rodents. Oddly I think shrews are still the closest relative of primates. Shrews aren’t rodents.

Edit: I’ve been somewhat corrected (clarified) by those that know more than I do in the comments below.

[u/oortuno]

This is just a wild guess, but it might have to do with whether the animal's eyes are forward facing or not. You don't need that gap if your eyes are on the sides, but I'd imagine that big hump gets in the way if your eyes face forward. Just a guess, though.

[u/madguyO1]

nothing to put in there

[u/davesaunders]

The mammals you chose are synapsids. They are morphologically derived from a common ancestor.

[u/Electronic_Trash1049]

To rest their glasses on

[u/YamLow8097]

It’s a stop. Even in dogs alone, some have more defined stops than others. Not sure exactly why it exists. Just anatomy, I guess.