D&D Monsters: Bulettes

The bulette is a creature original to D&D. Like the owlbear, it's based on a plastic toy from Hong Kong, in its case probably meant to represent some sort of kaiju, although it's hard to know for sure. It's one of a minority of original monsters to have an actual name right from the start, rather than a descriptive term ('mind flayer', 'carrion crawler', 'trapper'). 

Incidentally, Gygax originally intended the word to be pronounced as "boo-lay", and official material from WoTC, and TSR before them, used to insist on this - and maybe still does. This raises a question, often seen in fantasy literature more generally, of "then why didn't you spell it that way?" In this case, I'll note that both the spelling and the supposed pronunciation appear vaguely French, which may be intentional - although, obviously, they don't match up with one another in that language either...

---

1E

The original depiction of the bulette closely resembles the original plastic toy (shown). Said to be part turtle and part armadillo, it has a barrel-shaped body with no neck and legs that end in three grasping clawed toes. Heavy armour plates cover the head with its smooth, conical beak, while a triple row of bony scutes lies over the shoulders. The turtle shell is greatly reduced, seemingly only consisting of a partial carapace over the dorsal surface of the lower thorax and abdomen; the turtle's plastron appears to be replaced by the armadillo-like scutes.

The bulette is big, but not implausibly so; it's roughly the size of a rhino and, indeed, has the same hit dice. (On the other hand, if the picture shows a typical specimen, then it must have chased a halfling child up a fairly small tree). The bony armour is very thick, significantly better protection than even the very best steel plate, and the creature is evidently extraordinarily strong, both on account of the damage it can deliver, and its leaping ability - using a rhino as our benchmark, and figuring in the weight of the armour, it likely weighs around 3 tons.

The 2E version has a squatter build (which fits better with the stated height) and a serrated beak for tearing up flesh. The armoured scutes are much more irregular than in 1E, reducing the resemblance to an armadillo. We're told that a single bulette has a territory of "up to" 30 square miles (80 km²). This, it should be noted, is very much at the low end of what we'd expect for a tiger, which must surely require much less meat...

---

3E

The 3E version of the bulette has a segmented carapace that reaches right up to the head-shield, while scutes are only present on the shoulders and upper thighs. The unarmoured skin looks reptilian and the crest is also much less prominent. The toes are shorter, ending in heavy hoof-like claws that look fairly well-suited for the creature's burrowing lifestyle. Unlike the earlier versions, it has a proper tail, which is also covered in segmented armour.

Aside from these physical changes, the description of the bulette and its habits remains much the same. The statistics show that its strength is slightly higher than that of a rhino, while its hit points are about halfway between a rhino and an elephant. That's effectively an increase, but the creature's bite is significantly less deadly than it was before. The statistics also reveal that it has about the same intelligence as most mammals, and therefore more than is typically given to reptiles.

---

5E

In terms of appearance, the 5E bulette is essentially identical to the 3E form, at least so far as we can tell. It's less strong than it was before, now being outclassed by the rhino, and also much less agile. It may, in fact, be smaller, although the size isn't given, and the armour is notably less thick. The intelligence is now lower than for most carnivorous mammals, but on a par with, say, a crocodile. The bite is back to the large value of the first two editions in terms of damage, but since the creature no longer attacks with its claws (and they do look more suited for digging than fighting) that's not quite so bad as it might seem.

The crest is less prominent in 3E and 5E than it was before, which makes sense for something that has to burrow through the soil. A curiosity of the first two editions, scrapped in 3E, is that, when the bulette is in a really fierce fight, it raises the crest to expose softer skin beneath, apparently to give its opponents an extra advantage. It's hard to think why this would be, even as a maladaptive mutation to the original turtle/armadillo anatomy, and unsurprising that it was later swept under the carpet. On the plus side, the animal's territorial range is now "30 miles across", or roughly 700 square miles (1,800 km²), which is high, but perhaps more plausible for a predator of its enormous size than the previous figure.

---

Although it's specifically stated that nobody knows how bulettes reproduce, the limited evidence available suggests that they're reptilian. For instance, they have no visible hair that we can tell, and the beak would make it difficult for the infants to suckle. For that matter, if they spend much of their time insulated below the soil, warm-bloodedness may not be that big an advantage, either. This suggests, but does not prove, that they lay eggs, likely deep underground in sealed burrows where adventurers wouldn't find them.

Spending most of your life underground does have some advantages for an animal, such as avoiding bad weather and, more importantly, hiding from large predators. The latter is not a concern for bulettes, of course, since nothing much short of a dragon is going to be able to eat one, and there are a number of disadvantages associated with what's technically called the "fossorial" lifestyle as well.

For a start, soil only gets so deep before you hit bedrock. Assuming that bulettes are strong enough to shove aside heavy boulders but not to tunnel through solid, unbroken, rock strata, there are certainly some environments where the soil is deep enough to support the burrows of an animal so large. But not, it has to be said, very many.

You're generally looking for wide valleys or river deltas with substantial alluvial deposits, tropical and subtropical areas with very stable ancient geology, or places where glacial till has built up downslope from mountains. These would limit a bulette's range, especially in temperate environments, and if it wishes to stop its burrows flooding because the soil is below the water table (likely in, say, a delta). 

There's the additional issue that the burrow has to be deep enough for the soil above it not to collapse or for the tremors made in its construction to be obvious, yet shallow enough that the bulette can reach the surface quickly enough for whatever prey it has detected (via vibrations in the ground) not to have a chance to run away before it does so. There's a reason that no real-world creature even remotely approaching this size hunts in such a way.

Low oxygen levels are another problem with dwelling almost entirely in deep burrows. A bigger one, however, is the lack of light. It thus makes sense that bulettes are always shown with small eyes, similar to those of moles. (The ears aren't apparent, either; even if it's not a reptile, this is what we'd expect given the need for the streamlined head to help push through deep sediments. Again, look at moles.) Fortunately for the bulette, however, it has something real-world moles don't: darkvision.

The great majority of D&D monsters have darkvision. This is for game reasons; it allows them to sneak through lightless subterranean dungeons without them being obvious to adventurers from a distance. It's harder to surprise someone if it's light enough for them to see you coming, and even more so if you're, say, an orc that needs to hold a burning torch to light the way. But, nonetheless, the bulette is the sort of animal for which it would genuinely be ecologically useful, so this is as good a place as any to look at how darkvision might work.

To start with, it's important to distinguish darkvision from night vision, or low-light vision, if you prefer. Only 3E specifically makes this distinction, but it's clear that the description of the former doesn't match what the latter would actually be. 

Real-world nocturnal animals have night vision, for obvious reasons, and this includes such animals as cats and bats. This enables them to see in the gloom of the night, when it would appear entirely dark to a human. But what it can't do is enable them to see when there is no light at all. Cats may wander around happily in conditions where we'd just bump into everything, but put them in an underground labyrinth, and they would be as blind as we are. 

Darkvision doesn't have this limitation, because it would be largely pointless if it did. 

When you look at real-world animals that spend almost all their lives underground, such as moles, their eyesight isn't exceptionally good - in fact, it's rubbish. There's no point to having good vision if there's never anything to see. Things like blind cave crickets are another example of this, having lost their eyesight altogether, while mole-rats are able to sense light and dark, but can't literally 'see' anything in the sense of forming an image. (And they only need to detect light so that they can run away from it - if there's light in their tunnels, something's probably broken in to come and eat them).

This is not to say that no real-world animals have anything that's similar to darkvision. Bats, among other animals, do have an ability that's really not a bad fit, which is to say, biosonar. This can form an image of sorts, it doesn't require light, it doesn't include colour, and it has a limited range - all properties associated with darkvision. Indeed, in the RuneQuest game, biosonar is specifically stated to be how trolls see in their lightless underground passages.

3E gives bats darkvision, but 5E gives them 'blindsight' instead. In fact, it is clear that, for all the parallels, darkvision, as used by (say) elves, can't be biosonar. If it were, it would be stopped by a Silence spell, not Darkness, and could be foiled by gagging and/or blocking the ears of the person using it, not blindfolding them.

So how does darkvision work? 1E and 2E give a clear answer; still called 'infravision' in those editions, it's the ability to sense infrared light, and thus heat signatures. That would indeed be useful in a dungeon where warm-blooded adventurers might be found, but it's useless for seeing objects that don't give off heat... which, honestly, is most things that aren't alive. Darkvision as described in later editions is therefore obviously not this, either.

But sonar can, in fact help us. It was thought in ancient times that regular vision worked by the eyes sending out invisible rays that bounced off things and then returned the signal back. (Yes, this doesn't make much sense in hindsight, but that's what they thought). The fact that darkvision has so many of the properties of sonar - which really does work like that - could imply that, in the D&D universe, it works the way that the likes of Euclid thought real vision did.

The actual radiation given out by the eyes under this theory is not of a type that exists in the real world. There also needs to be a means for the viewer to block out the radiation emitted by the eyes of other darkvision-users, or it would be hard to make anything out clearly in the muddle. But bats can do exactly this with sonar, even though we don't quite know how, so clearly it's possible. (It's sometimes called the 'cocktail party nightmare' and I discussed it a few years back over on my science blog).

The fact that, at least in the 5E rules text, darkvision does allow the user to perceive 'shades of grey' (rather than just shapes) implies that this radiation is absorbed by the same sorts of things as light is. It may not interact with colour, but black is still black. This also explains why the Darkness spell works against darkvision, since it absorbs whatever this radiation is along with light rays.