Diablotaurus vespa - Devil bull

## Etymology, discovery and naming

The genus name Diablotaurus traces to Greek διάβολος ταύρος (diávolos távros). This translates to "Devil bull," as it has five horns. The species name vespa comes from the Latin word for wasp, for the deep blue circles on its horns and towards the end of its tail that signal sexual availability, help in cooling, and help dissuade hungry predators.

The family of creatures were discovered during the second expedition to Wallace II. Dr. Bob Smith gave them the name because of their appearance, with Diablotaurus vespa as the type species.

Males devil bulls are called Bills, females are called Jills and young of either gender are referred to as calves. A group of devil bulls that reside together is called a herd.

## Evolution

Devil bulls are members of class Planacorporia. Their closest known relative are members of genus Aquaovium, water sheep. Both have atrophied second leg pairs, a very similar skeleton, and the same dental formula. Both fossil and molecular phylogenetic studies support the hypothesis that the common ancestor of water sheep, bouncers, boomer bugs and diablotaurus split approximately 75 million years ago and that the common ancestor of water sheep and devil bulls split approximately 22 million years ago.

## Description

**Anatomy**

Devil bulls have a heavy, barrel-shaped body and broad, deep head with two proboscises. and the four heart, two lung system of respiration and circulation that is distinctly Planacorporian.
Like bouncers and water sheep, devil bulls have a three chambered stomach. The first chamber is the gizzard. Gastroliths that the bouncers swallow grind and break down their food. Material that the gastroliths can't sufficiently break down are returned to the devil bull's mounth for secondary chewing. The second chamber is the rumen. It is the largest stomach compartment. Microbes ferment the food and produce volatile fatty acids, which are the devil bull's main energy source. Finally, food travels to the abonasum or true stomach. The abomasum is lined with glands that release hydrochloric acid and digestive enzymes. These secretions break down their food.

Devil bulls have many features that are unique in planacorporian anatomy. Their ear flaps along with the respiratory and olfactory inlets are on their frills. It is theorized that the rear end of their skulls evolved to stretch backwards to balance the increased weight of their lengthy proboscis horn and their brow horns. They also have a heavy thagomizer at the end of their tails.

**Dimensions**

An adult bill typically stands at about 2.75 meters tall at the withers, and typically mass about 2.5 tons. From the tip of their rostrum horn to the end of their tail, they are about nine meters long. Jills are smaller and more gracile, at about 2.1 meters at the withers, mass 1.5 metric tons and seven meters long. Like water sheep, devil bulls are hexapeds, with six feet on the ground. The second pair of limbs are usually visible but are vestigial and are useless. Their forelimbs that are more sprawled than their hind limb sets, which are directly under the body.

About a meter of the length of a bill is his proboscis horn. This ancestral feature for skewering prey atrophied in most of the later planacorporians, but re-emerged as a defensive weapon among devil bulls. It has a core of solid bone, with a thick keratin sheath. The same type of keratin sheath also covers their face, frill, and thagomizers.

**Gigantothermy**

Devil Bulls are gigantotherms. They are ectothermic, but are easily able to maintain a constant, relatively high body temperature than smaller animals by virtue of their smaller surface area to volume ratio. This gives them the advantage of being virtually homeothermic. They have a slower metabolic rate, and eat only about a quarter as much as a comparable sized mammal. Herds will soak up the free energy from sunshine while grazing or chewing their cud.
They can maintain the performance of an endotherm during long term exertion such as fleeing a predator because the exertion raises their internal body temperature. As devil bulls will dump excessive heat by flushing the blood filled keratin on their faces, frills, horns, and thagomizers, it is theorized that these may have developed for thermal regulation and then were secondarily selected for defense against predation.

**General morphology**

*Hide*

The skin of devil bulls has the same form of tough denticles as the rest of Saburramhabitatoria, but it is extremely thick. In the thickest part, over their back, it can reach 4 cm thick. Their denticles have a background of brown to light tan, blended with a dark green, olive green, and lime green gradient and a scattering of dark brown and cream-colored shapes spread throughout the pattern. This allows for the overall appearance to change from predominantly green to predominantly brown in different areas of their bodies, while having smaller shapes break up the larger background areas. This provides concealment at both short and longer ranges.

While most other land dwelling planacorporians had denticles on almost their entire body, devil bulls have a thick coat of keratin over their horns, face, frill, the very end of their tail and their thagomizer. When they are overheated or their blood pressure rises because they are excited, mating, running hard, or in combat, spots under their keratin flush deep blue with blood. The species name of the type species, D. vespa, comes from the blue ring that flashes in the yellowish tan keratin at the base of their tail and the bands in their horns. The blood flushing makes their frills look like another face. When a devil bull with a face that is flushed with excitement stands erect, it looks like the top of their heads are four meters tall.

*Dentition*

Like bouncers and water sheep, their dental formula is 1.0.1.3 and their incisors keep growing throughout their lives. Domesticated specimens must be given tough materials to gnaw on to keep their teeth short or they will injure themselves.

*Sexual characteristics*

As is typical among planacorporians, devil bulls don't have pronounced secondary sexual characteristics and their genitalia is kept within a genital flap. Males are noticeably larger, with proportionally larger frills, horns and thagomizers.

*Senses*

Devil bull vision is poor, but they can see in a 300 degree arc around them. They have excellent hearing and sense of smell. Their ears and nostrils are at the tops of their frills. This means that the ears and nose of a large bill are over three three meters high while they are grazing, giving them a considerable advantage in detecting predators.

## Behavior

**Social and reproductive behavior**

The core of devil bull herds are the adult jills, with the older adult matriarchs as the leaders. Jills will remain together in a herd group with their maternal family for life. and typically compose of 50 or so adult females. Young bills will leave their birth herd and join bachelor herds during late winter or early spring during their second year.

As mating time approaches, members of bachelor herds will transition to family herds. No serious injury due to fighting between bills has been recorded, with size and shoving matches being the major factor in determining dominance. Older bulls are not driven from the herd by younger ones. Younger bulls instead achieve domination by virtue of their size and strength.
Devil bulls are notable for their apparent altruism. Jills appear to exhibit some sort of "voting behavior". During resting time, the females stand up, shuffle around, and sit back down again. They sit in the direction they think they should move. After an hour of more shuffling, the females travel in the direction they decide. This decision is communal and not based on hierarchy or dominance.

**Mating, reproduction, and development**

Sexual maturity occurs in the devil bull's second year. Jills are ovoviviparous and have one calf, rarely two, after a gestation period of about 300 Earth days. The lifespan of a devil bull in captivity is up to 30 years.

Breeding takes place year-round, but typically peaks during the local winter. Bills will use their thagomizers to crush open bone trees, gazellia and antleria and let jills who are in season eat from trees. Jills prefer bulls that can bring down the largest trees the quickest. This courtship ritual selects for size, strength and coordination.

Devil bulls keep a harem of up to half a dozen reproductive females. The bill will monitor his own offspring to ensure their well-being until they approach maturity.

**Territorial behaviors**

Each herd has a nonexclusive home range, and sometimes herds may join in groups of 500 or more.
During the dry season, herds congregate and remain in small areas, dispersing into the hills with the arrival of the monsoon. While devil bulls need water for drinking, they do not bathe or wallow.

**Intelligence**

All studies indicate that their cognitive abilities are extremely limited, in the range of Earth bovines. The brain of an adult male devil bull weighs almost two kilograms, but at 0.9 their Encephalization quotient is about that of a horse's. Anatomical studies of their brains find that they have immense olfactory bulbs, hearing lobes, taste processing centers as well as motor control areas. Their centers for cognition and planning are small.

## Ecology

**Habitat**

Devil bulls are native to Media Insula. They live in river valleys, swamps, floodplains, as well as mopane grasslands, and the forests of the major mountains of Media Insula as well as savannahs, prairies and plains. While they prefer habitat with dense cover, such as reeds and thickets, they can also be found in open woodland, semi-open grasslands, as well as sagebrush, semiarid lands, and scrublands. They also graze in hilly or mountainous areas, as their six feet give them remarkable traction and agility on moderate slopes. Herds are frequently found at elevations above 3,500 meters.

**Diet**

Devil bulls graze and browse on a wider variety of plants than any other large herbivore species, with a preference for the upper portions of polyspeculates, such as leaf blades, stems, seeds and flowers of grass species. They will eat Sidobosia, and are quite fond of rustlers and climbing devourers.

**Efficiency**

The devil bull is one of the most successful herbivores on Wallace II. They can eat almost anything and their water needs are modest.

**Feeding behaviors**

Devil bulls will perform a "push up" with their front feet while grazing, lowering their face to the ground as they carefully sniff their food with the top of their frill. They browse effectively with the aid of their meter-long tongue.

**Predators**

Devil bulls have a predator/prey relationship with Quetzal viatorem. Attacks typically come during storms, when high winds, thunder and rain mask their smell and sound. The hunting pack will carefully choose a target, usually an elderly or young individual that towards the edge of the herd. Approaching upwind, they will make a coordinated strike.

Devil bulls will engage in mobbing behavior when fighting off predators. Bills have killed been recorded killing Q. viatorem or chasing them up trees.

When predators such as Q. viatorem are detected, devil bulls will circle around calves and new mothers, horns out, bodies broadside and thagomizers raised to strike. The sound of their collective alarm whistles is deafening.

## Communication

**Body language**

Two devil bulls leaning against each other is believed to be the equivalent of a hug.

Wagging their tails is a sign of stress, and often signifies pain. So does standing with an arched back and a lowered head.

When they tuck their tails between their legs, it means that they are cold.

A devil bull that holds its body broadside towards you with its head towards you and lowered is a sign of potential aggression. If they shake their horns at you, paw the ground or raise their thagomizer, this is a warning of aggression.

A tail that is somewhat raised yet where their thagomizer is below head height indicates that they are alert or exploring.

**Vocalization**

Devil bull calls are loud and deep. Many are so deep that human ears can't detect them. While their anatomy is capable of producing the complicated simultaneous polyphonic calls of bugs, boomers and razor jaws, they have never been observed doing so.

The matriarch jills emit low-pitched, two- to four-second calls intermittently at three- to six-second intervals to signal the herd to move. To signal to the herd to change direction, they emit "gritty", "creaking gate" sounds. When moving to drinking places, some individuals make long "maaa" calls up to 20 times a minute. When being aggressive, they make explosive grunts that may last long or turn into a rumbling growl. Jills produce croaking calls when looking for their calves. Calves make a similar call of a higher pitch when in distress. When threatened by predators, they make drawn-out "waaaa" calls.

Dominant bills make calls to announce their presence and location. A version of the same call, but more intense, is emitted as a warning to an encroaching inferior. Males make a mating call of clear, resonant tones which may carry for more than five kilometers.
When grazing, both sexes make various sounds, such as brief bellows, grunts, honks, and croaks. To warn other members of its herd of approaching danger, they let out a high whistle for help and beat their thagomizer on the ground. The whistles and deafening thumps echo through the herd as they form their characteristic defensive line.

## Danger to Man

Devil bull temperament is often unpredictable. They usually appear peaceful, unconcerned, even lazy, yet they may attack anything, often without warning or apparent reason. Bills are especially dangerous if the herd is approached when a jill is about to give birth or a calf that has just been born.

Bills can move at speeds up to 60 km/h and cover long distances at a lumbering gallop. They have been documented punching their meter long proboscis horn through the solid metal door of a ground car, killing the occupants. The bill then withdrew his horn and calmly left, uninjured. The leaping power of their powerful rear legs give them incredible agility and have struck people with their thagomizer while in midair.

## Domestication

After the genetic sequence of dozens of D. vespa were published, food production companies on several planets replicated examples. They have proven to be quite successful as an Agra-business commodity crop. They produce about four times as much meat on a unit of feed as Earth bovines, and taste like high grade seafish. They have proven to be rugged, disease resistant, predator resistant, and able to thrive on wasteland that is too arid to graze anything else.

The very features that make them well suited as livestock also make them difficult to manage. Fencing herds of three-meter tall animals has proven difficult and expensive. If a herd wants to go through a fence, they will slam into it until it topples. Common barriers like cattle grates don't phase their massive feet. Instead of speeder bikes or horses like traditional cowboys, herders have to drive armored personnel carriers.