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My species of caniform-like creature has a relatively long muzzle because of its strong sense of smell. I would like to know how to give it a long muzzle with its large brain size. Members of this species primarily communicate with each other through certain electromagnetic waves, bodily scent, and occasional sound such as clapping or yelping. This species has relatively poor eyesight with red-green colorblindness. They are bipedal and have opposable digits on their forelimbs.

As well as being scientifically inclined at the level of modern day humans (of course with technology catering to its own forms of sensory input), members of the species would be able to understand many human concepts, form cultures, and create complex, intelligent concepts of their own. To put it bluntly, this species has 'intelligence' on par with humans.

More to the issue of the muzzles; this species does not hunt with a powerful bite because of tool use. It does have a mesocarnivorous diet with the appropriate dentition, so if anything about the diet would influence musculature, please indicate so. Regardless, I would expect it to require more muscles to support its snout. Neck muscles would already be highly developed because of the horn-like antennae on this creature.

Assuming the musculature of the mouth is much like that of existing carnivorans, for the most part, I am wondering:

  • If the muzzle is at all plausible with a large brain
  • If the muscles of the snout just be too heavy or large for the head
  • If any 'space saving' adaptations such as putting brain tissue in the spinal area would work
  • If the head would be too ridiculously large to support at all

I hope this is clear enough.

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    $\begingroup$ Roki, what is it that makes you believe muzzles have anything to do with intelligence or a large brain? Please explain why you're asking the question, because this feels like a non-question. (It's worth noting that the nature of evolution is such that, given enough time and the right stimulus, pretty much anything can evolve. There are no super-tech/gifted-with-reason species other than humans on Earth 'cause we basically won the genetic roll of the dice and now we're going out of our way to ensure nothing else can challenge us.) $\endgroup$ – JBH Jul 27 '18 at 5:24
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    $\begingroup$ @JBH It may come as a surprise the OP is quite right. There is a relationship between brain size and the size of a muzzle. This has been proved in hominin species. This is a real question. A small knowledge of human evolution is helpful in understanding this. meanwhile VTCers can back off. I will post an answer when I have time. But not now. $\endgroup$ – a4android Jul 27 '18 at 7:32
  • $\begingroup$ @a4android: I doubt there's a causal relationship between brain and muzzle size. Apes and chimps are much more likely to use their mouth / teeth as weapons (note that evolving homo species tend towards progressively smaller canine teeth). Humans use tools, and have vastly more efficient co-operative hunting strategies because they have language. Which of course does require a larger brain, though I'm not convinced large-brained Neanderthals had any significant linguistic skills, since their larynx was too high in the throat to permit much variation of vocalisations). $\endgroup$ – FumbleFingers Jul 27 '18 at 17:59
  • $\begingroup$ @FumbleFingers Sorry, buddy, you're wrong. Your arguments may sound plausible, but you're looking in the wrong places for a solution. $\endgroup$ – a4android Jul 28 '18 at 2:29
  • $\begingroup$ @a4android: Wrong about what? Are you going to insist Neanderthals were as linguistically competent as modern homo sap? We now has DNA evidence supporting my position that they weren't (genes relating to language figure significantly in those genes where we differ from them), plus I think there's more support from internal skull architecture. And there's no evidence that Neanderthals used "arbitrary symbols" (for language or anything else), and personally I think recent claims that they had "representational art" (cave paintings, etc.) are tenuous at best. $\endgroup$ – FumbleFingers Jul 28 '18 at 13:39
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A plausible reason for the negative correlation between anthropoid muzzle size and brain size is quite simple, the higher the intelligence, particularly if high enough to cook, the less need there is for large teeth, chewing muscles, or heavy support in the skull. When teeth stop being your primary weapon (offensive or defensive), and no longer have to crack hard shells or masticate on raw vegetables, when tools and fire replace those functions, the evolutionary need for heavy jaws, a powerful bite, and large teeth is much reduced.

And evolution is efficient in the long run; use it or lose it.

I will present a counter-example, another mammal with very high intelligence, with apparent consciousness, tool use, cooperation and a rather large muzzle: Bottlenose dolphins. There are numerous experiments suggesting they have an abstract language (more than specific nouns or verbs, a descriptive language that allows them to describe procedures or objects they haven't seen before to another dolphin). I think there is no debate they are highly intelligent, provably inventive to solve problems, which to our knowledge requires self-awareness in a biological intelligence. (Solutions can be found by computers by simulating millions or billions of trials and errors, but no biological intelligence works that way, certainly not humans or mammals).

Elephants are likewise highly intelligent, problem solvers with self-awareness; and the elephant's trunk is an extended version of a nose.

There is also strong scientific doubt about correlations between brain size and intelligence. The vast majority of brain size is most strongly correlated with body-size, much less so intelligence. Large bodies have more nerve endings for both sensory functions and muscle command, and for processing the larger number of incoming signals. Due to accidents, gunshot wounds, cancers, strokes, etc, some unfortunate humans have lost nearly half their brain mass, and still recovered to be walking, talking professionals with above average IQ.

Large brains do not correlate with IQ; the average human brain is 3 pounds, and the average elephant brain is 4x bigger, at 12 pounds. And although elephants make and use tools and have a complex social life, if they were 4x as intelligent as humans, or 1x as intelligent, they would not be an endangered species and like the first homo sapiens would carry sharp weapons against predators.

You should consider relative brain mass (as a percentage of the rest of their body mass), not total brain mass; and as humans (both injured and whole) prove, there can be a factor of two or three even in that relative figure.

I think a large muzzle and intelligence are evolutionary compatible.

It is a large mistake, IMO, to short-change evolution and consider only the single human path toward intelligence, self-awareness and abstract thinking.

Evolution will find a way to solve any problems. That said, your creatures should not have features just because you think they'd be cool, you need a plausible reason a large muscular muzzle is NOT discarded over millions of years, it must have a plausible survival value that cannot be replaced by brain power -- and nearly all muscular functions can be. Compared to other creatures we dominate (including others like us, chimps and gorillas) we are weak, poorly sighted, slow, absent natural weaponry like teeth and claws, with seriously deficient hearing and olfactory senses, all in large part because abstract reasoning easily trumps all those tools, and we have declined from the "size and senses matter" body plans to our current state because we don't really need all that muscle. That is not a one-example rule, dogs have done the same, they may be descended from wolves but most domesticated dogs could not keep up with wild wolves in hunting or battle even if born to the life; they evolved away from that because they don't need it.

Simply needing a long snout to preserve the olfactory sense is not enough; it doesn't explain the need for a muscular jaw, large teeth or heavy jawbones. The elephant has a fine sense of smell without a bone in its nose, many fish have superb olfactory senses in very small packages, as do short-snout and very small dogs.

I won't propose any solutions, that is your creative job, but if there is a good plausible evolutionary reason to have both of these features together, I would presume that evolution would find a way.

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If the main reason for a muzzle is the olfactory sense, you might want to look at skulls of polar bears. They have one of the strongest olfactory sense among animals, but their muzzle isn't overly long. Instead, the nostrils are quite wide and the tissue heavily folded to get more area to have more olfactory cells in a limited space.

The skull offers enough space for a large brain without the need for big muscles to hold it up.

Balancing heavy horn-like antennae could pose a problem because they shift the center of balance. So the strength of the neck mainly depends on your design of their antennae.

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Assuming the musculature of the mouth is much like that of existing carnivores, for the most part, I am wondering:

If the muzzle is at all plausible with a large brain
If the muscles of the snout just be too heavy or large for the head
If any 'space saving' adaptations such as putting brain tissue in the spinal area would work
If the head would be too ridiculously large to support at all

This answer will deal specifically with the relationship between brain size and a muzzle. Viz., Is the muzzle of a carnivore plausible with a large brain? The simple answer is no. This can be demonstrated by looking at human evolution.

This will be a simplified picture of that evolution, but this should suffice to explain the general principles involved. Essentially over the period humans from ape-like primates to modern humans cranial capacity, i.e., brain size increased while the size of their jaws decreased. Our oldest ancestors possessed prognathous jaws or what can be called basically big jaws that stuck out from their faces. This is the equivalent of a muzzle. By comparison, modern humans have flat faces and small jaws along with a greatly increased brain size.

Essentially hominids with large jaws had small brains. As they evolved into humans brain increased and jaw size decreased. Basically cranial capacity was constricted by the large muscles needed to support their large jaws. Modern humans' big brains and small jaws were anatomical features that co-evolved to make us human.

Human evolution in a snapshot

Source: Human Evolution

In the early days of human evolutionary studies there was discussion whether hominids evolved their big brains first or if the size of their protruding jaws became smaller first.

The Piltdown Man forgery was an unfortunate distraction to progress in the understanding of human evolution.

The "large brain first" view received further support when the Piltdown fossils were presented to the world. While we now know that they are fraudulent, at the time (1911) they seemed to demonstrate quite clearly that early humans had a modern cranium atop an ape-like body. And since the Piltdown remains were found in England, they conveniently supported the prevailing idea that modern humans had evolved in Europe, rather than in Africa.

This made acceptance difficult that humans evolved from more apelike creatures that progressively lost their more apelike features especially their prognathous jaws and their acquisition of less muzzle-like lower faces.

Consequently, when in 1924 Raymond Dart recognised the position of the Taung baby (Australopithecus africanus) on the human family tree, his ideas initially faced considerable opposition. Not until more australopithecine fossils were discovered did his recognition of A. australis as a hominid gain credence. However, it is now accepted that the ancestors of modern humans evolved in Africa and remained there until perhaps 1.5 million years ago, when Homo erectus populations left Africa and moved rapidly across Europe and Asia.

Consider Australpithecus afarensis as an illustration.

The best-known member of this species is "Lucy" , discovered in 1974 by Don Johanson & Tom Gray and estimated to be around 3.2 million years old (afarensis lived from 3.9 to 3 million years ago). This is an important find as the skeleton is remarkably complete for its age (40% complete by some estimates, but this does not include the bones of the hands and feet), providing a wealth of data about her size, posture, and gait.

Generally their sizes in terms of body height and brain sizes are as follows:

Afarensis remains indicate that the species was strongly sexually dimorphic, with males much larger than females. The remains indicate that afarensis heights ranged from 107 to 152 cm, and cranial capacity from 375 cc to 550cc (AL 444-2, a large adult male).

With the following facial and cranial features:

The face and cranium of afarensis was ape-like: a prominent brow ridge, low forehead, and a prognathous muzzle that lacked a chin. The teeth are intermediate between ape and human: the molars are large and the canines, though much smaller than those of living apes, are larger and more pointed than those of humans. The shape of the dental arcade lies between the human parabolic form and the apes' rectangular shape, and the foramen magnum, while further forward than in apes, is not directly under the cranium as in humans.

Interestingly the rest of their skeletons show features much more akin to a modern humans' than an apes. Although there are indications that they spent time in trees.

A summary of the differences between our Australopithecine ancestors and ourselves.

Australopithecus

Foramen magnum more forward –Australopithecus is mostly bipedal but relies on nuchal crest / neck muscles to keep head upright.

Homo Sapiens (us!)

Foramen magnum is centred under the skull – H sapiens is fully bipedal with head balanced on spine.

Skull Human

rounded brain case (enlarged brain) with reduced sites for muscle attachment, especially those used for chewing and aggressive facial displays which are no longer called for.

Ape

Flatter brain case (smaller brain) which allows for greater muscle attachment sites needed for aggressive facial displays.

Importantly a carnivore with a muzzle will need greater muscle attachment sites to support that muzzle and to give it the biting power that a carnivore needs to either devour its prey or kill them. This will mean carnivores will have smaller brains.

In summary, larger brains are not plausible for carnivores with large muzzles.

Would the muscles supporting the muzzle be too heavy or large for the head?

This seems likely, but it is highly contingent on the size of the muzzle and the size of the brain case. Both features are antagonistic to each other. If the carnivore had both a sufficiently big enough and a big enough muzzle, then the whole structure could be very unwieldy. This isn't plausible.

In summary, yes but extremely improbable.

The 'space saving' adaptations of putting brain tissue in the spine seems implausible. One, because brains should be as close as possible to an organism's main sensory receptors. This is a general rule of thumb biologically. Two, it doesn't seem like there's sufficient room there to house additional mass.

However, some of the larger dinosaurs did have secondary brains located on their spines. Otherwise they would have had coordination problems managing their large bodies. Possibly a series of secondary brains could be located along an organism's spinal column. This wouldn't make the creature smaller, but more likely better coordinated. Perhaps if its cortex was located in the smaller brain case needed by a carnivore, then other major neurological features of the brain could be in its secondary brains. Notionally, but not at all certain if this is biologically plausible.

Also, octopuses have a highly distributed nervous system that extends through their bodies. This suggests a brainy carnivore might have evolved to have a similar highly distributed nervous system. Then, again, only its higher executive functions might need to be housed in the smaller brain case required by a carnivore.

In summary, while additional brain matter located in the spinal area seems implausible, there are two possible models for the relocation or emplacement of additional or extended neural systems. Please note: the organism would be different from most carnivores we know. This is very hypothetical.

If the head would be too ridiculously large to support at all?

Actually it's the combination of a big brain and a carnivore muzzle that is, sad to say, ridiculous. This has been covered in the discussion to the second part of your question. The combination of a big brain and big jaws is inherently contradictory. No impossible, but so full of problems for the organism with other features to be a hazard to its survival.

If such a creature existed it would need other anatomical features to protect itself and to be able to support a massive head. Perhaps a bigger body with powerful musculature?

In summary, more improbable and implausible than too ridiculously large.

However, this is purely speculative. If your hypothetical carnivore had a radically different body plan from the types of carnivores we know on planet Earth, then it might possess an anatomy where the equivalent of a carnivore's muzzle was separate from its brain case. Once the muzzle and brain case are separate structures they can each evolve to considerably larger sizes. The result could easily be a sapient carnivore with both a big brain brain and big muscular jawed muzzle. It would look very strange indeed.

This answer has considered the possibility of an intelligent carnivore with a muzzle and a large brain in terms based on features found in human evolution. While offering some possibilities about how this arrangement might work, its conclusions are generally negative about this working in combination.

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One issue in the design of skulls is ensuring the weight is kept in controllable limits, so evolutionary pressures for light weight result in voids known as "sinuses". For a fairly extreme example the skull of the T-Rex had both a very elaborate system of sinuses for mass reduction, coupled with some extreme engineering to provide attachment points for massive muscles in the jaws, and the strength to deliver bites powerful enough to crunch through solid bone.

enter image description here

The large sinus cavities are prominently displayed here

So in principle, there is nothing to really stop that sort of adaptation from evolving, assuming the need for a highly sensitive sense of smell coupled to high intelligence is evolutionarily favourable.

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