by Steve White
OTHER FAUNA
PREDATORS
Ceratosaurus is rare but there are two other Theropods even rarer. Stokesosaurus and Marshosaurus are two predators of indeterminate classification. Little is known of them and sightings of them are scant. Both are small but definitely not Coelurosaur-like; one seems to live in the thick gallery forests of the Front Range while the other has been seen twice out in the far ranges of the Foredeep. It is not even certain which species is which but the forest type is definitely feathered.
More common are the Coelurosaurs, particularly Coelurus, Ornitholestes, and Tanycolagreus. These swift predators generally hunt small, fast prey as large as Dryosaurus but also running crocs, Nanosaurs, mammals and the young of other, larger dinosaurs. The smaller types, Coelurus and Ornitholestes are lightly built and represent little threat to hunting teams, both growing no more than 8ft and 40lbs. However, Tanycolagreus is a larger animal, over 12ft long; it preys principally on small to medium-sized Ornithopods, but is a major threat to hunters on foot in open woodland and the interior of the Foredeep.
SAUROPODS
The most important members of the Morrison fauna are the Sauropods. Massively impressive to look at, they also have a profound impact on the landscape. With as many as half a dozen species of these thunder lizards, some travelling in large herds at certain times of year, they can cause catastrophic damage to woods and forests. The biggest can bulldoze great trails through the thickest forest, forcing down old growth conifers. However, in doing so, they open up understorey species to the sun and allow dormant seeds to germinate and replace the fallen gallery forest giants; this also forms new habitats for smaller Sauropods and Ornithopods. These giant herbivores also leave huge amounts of dung to act as compost and fertilizer for the new growth.
All the Sauropods breed more or less together. Males of all species have long dewclaws and like Theropods use them to stabilize themselves during mating; accordingly, females also have thick skin and in some cases armour over their shoulders to protect themselves, although many carry mating scars.
After mating, pregnant females move into the forested foothills and gallery forests to make simple nests, which vary from species to species, ranging from simple hollows with the eggs laid in a spiral, to more sophisticated mounds of vegetation. Some smaller species such as Camarasaurus and Diplodocus nest in rough colonies in more open woodland, but usually close to denser forest and permanent watercourses.
However, no matter the laying strategy, no matter the species, the eggs are all timed to hatch at night. This mass hatching means no one species is singled out for attention by predators.
Known species include:
Apatosaurus: Grows to about 70ft long and weighs to 30 tons (although larger individuals may be present). Apatosaurus is an opportunist feeder, browsing both horizontally at low level and in the vertical axis by adapting a tripodal posture, using its tail as a crutch to allow it to reach high into the tree canopies. It is, by and large, solitary in all stages of growth, but also very widespread, being tough enough to withstand the extremes of the fern prairie but robust enough to shoulder its way into deeper forest. Males fight in the tripodal stance, using their very large dewclaws as weapons in territorial and breeding disputes; this posture, together with the large dewclaws, also makes for an effective deterrent against predators. Breeding-age adults gather at the edges of the Foredeep for courtship and mating at the end of the dry season; pregnant females migrate into the woods and forests to lay their eggs in simple trench-like nests amongst dense understoreys; these are abandoned on laying. The males often stay out on the Foredeep, foraging on the wet season’s new growth of ferns; many head into the woods and forests for the dry season.
Diplodocus: Grows up to 90ft and weighs 10–15 tons; however there are a number of very large individuals (usually males) over 110ft that have been sighted; these ‘supersaurs’ are not a separate species but just very large and very old individuals.
The most common Sauropod of the Foredeep fern prairies and more open woodlands, with its long, almost-horizontal neck and its narrow head and peg-like nipping front teeth, Diplodocus crops and strips off low vegetation, although it can adopt a similar tripodal stance to Apatosaurus if hungry enough (as with the latter, this stance is used in intra-species combat and to deter predators).
Mating and breeding follow the pattern of most of the Sauropods, although Diplodocus females migrate into the Front Range highlands and gather in loosely associated colonies to nest in open woodland. These colonies are often close to denser brush and forests, which provide the young with a chance to make cover when they hatch. Unlike forest-nesting species, Diplodocus eggs hatch at dawn so that the big-eyed young have a chance of seeing and smelling the forests nearby.
The teeth arrangement of the young is very different to the adults, allowing them to feed on a broader menu of plant types, thereby fuelling their rapid growth rates. The juveniles usually stay in cover for a number of years until they are large enough to form into age-specific unstructured herds of juveniles and risk more open ground. These herds tend to travel out into the Foredeep where the young graze on the fern prairies in the wet season and move back into the woods and forests in the dry season. These juvenile herds are a common sight in the Morrison. The young are also quite aggressive to predators, rearing up or using the legendary ‘whiplash’ tail of the Diplodocids (to which Apatosaurus and Barosaurus belong) that, as the name implies, is used to lash out at predators as a deterrent.
Barosaurus: Grows up to 85ft and weighs about 22 tons. Barosaurus is instantly recognizable by its extraordinarily long neck but has a more slender build than Diplodocus and tan and beige markings. The long neck has broad lateral but little vertical movement; it is most definitely a low-grazer and spends most of its time in open woodland or the interior of the Foredeep especially during the wet season, where it generally feeds on ferns and cycad and tree fern crowns. It is far less common than its Diplodocid relatives and travels in small herds or alone.
Nesting usually takes place by permanent watercourses lined with riverine forests that provide cover for the newly hatched young. Hatchlings are born with much shorter necks and are similar to Diplodocus young in diet.
Like other Diplodocids, Barosaurus has a whiplash tail to deter predators.
Haplocanthosaurus: Grows up to 50ft and weighs about 12 tons. This is one of the smaller and the rarest of the Morrison Sauropods. It is also the most generalized and inhabits the broadest range. Little is known of its habits and reproduction. Camarasaurus: Grows up to 50ft and weighs about 20 tons. Herds of this Sauropod are a common sight in the forests and woodlands of the Morrison throughout the year, and at the edge of the Foredeep during the wet season. Although roughly the same size as Haplocanthosaurus, it has a far more robust build and more unusual body plan. While most other Sauropods have four equally sized limbs or slightly smaller forelimbs, Camarasaurus is raised at the withers, naturally deflecting the neck upwards. The head is also boxy and blunt‑snouted, and the teeth are chisel-topped and spatulate-shaped – very unlike the narrow, refined heads of Diplodocids. These differences allow a separation in the ecology of these Sauropod types. Camarasaurus is a true browser, feeding principally in the vertical, high-browsing tree canopies as far as it can reach, its stout teeth breaking up twigs, bark and cones as well as leaves. Physiologically it finds it difficult to browse low or graze like the boom-necked Diplodocids, which restricts its range to woods and forests. Camarasaurus herds will enter the Foredeep but stay close to riverine forests or open woodland.
This species is also most responsible for the damage done to the forests and woods of the Morrison (along with, perhaps, Apatosaurus); herds will shoulder down smaller trees and strip the lower branches but this is vital in maintaining the health of the Morrison ecosystem.
Camarasaurus is a particularly aggressive Sauropod (be warned!); lacking a whiplash tail and limited in its ability to rear like Diplodocids, it will use its strong j
aws and teeth to inflict a nasty bite.
Camarasaurs nest colonially in the highlands of the Front Range, often close to Diplodocus colonies, where the two species presumably offer mutual protection against predators.
The young spend their early years in deeper forest and wooded areas, swamps and marshes, growing fast but not reaching sexual maturity until at least two decades old. During this period, pre-breeding-age individuals form herds of similarly aged animals.
Brachiosaurus: The likelihood of seeing one of these truly giant Sauropods – the biggest in the Morrison and one of the biggest ever – is remote as they live in deep conifer forests where they browse the very tallest of trees. These forests are largely outside the range of the hunting reserve, but special trips can be arranged to try to see one of these behemoths.
Killing any Sauropod is strictly forbidden unless deemed in self-defence. This may seem like stating the obvious but the sheer immensity and majesty of Sauropods make them tempting targets.
ORNITHOPODS
Stegosaurus grows to about 30ft in length and weighs about 5 tons. This iconic dinosaur is instantly recognizable and fortunately quite common in the Morrison. It’s also the formation’s largest non-Sauropod herbivore.
Stegosaurus is easily identifiable by the alternating row of plates that run across its back and down its tail. These are sexually dimorphic. The female plates tend to be smaller and more leaf-shaped, coming to a point on top; the male’s are much larger especially over the hips, and more diamond‑shaped. The latter’s are also far more colourful and used in sexual display and threats. The female’s plates represent a more defensive shape; they are boldly marked but more as a deterrent to predators.
Female Stegosaurs also tend to be smaller than the males but both sexes are equipped with thagomizers, the array of four tail spikes named after a famous Gary Larson Far Side cartoon. These spikes can measure as long as 3ft. The tail itself is structurally quite ridged but flexible at the base so that it can be swung horizontally with a flick of the hips, propelled by the animal’s powerful back legs with their massive thigh muscles. Tactically, however, it’s the forelimbs that do the work, pushing off and pivoting Stegosaurus around its hip-based centre of gravity, and keeping the thagomizer towards its attacker.
Generally a quadruped, it is also quite a capable biped. It will rise up on its hind legs as part of a threat display to predators (and, in the case of males, to rivals), and to browse the crowns of cycads and tree ferns. It is, however, primarily a low-browser/grazer, feeding on ferns, horsetails and ground pines. For this it uses its tough keratin beak to pluck off plant matter; the teeth are relatively simple and used solely to cut up leaves before they are swallowed into its fermentation vat gut.
Stegosaurus mating is a gentle, careful business, the plates a definite nuisance during sex. If you’re visiting at the start of the wet season, it’s worth trying to find a pair mid-coupling to watch this balletic display.
The female nests in deep shrub or forest, laying her eggs in a mound of vegetation; she stays with the eggs until they hatch then abandons the young. The hatchlings stay deep in riverine forests and dense understoreys; they also spend a lot of time in marshes and swamps, which provide a degree of safety from large Theropods and Coelurosaurs, but makes them vulnerable to crocodilians.
There is a possible second species of Stegosaurus very similar to the African Stegosaur Kentrosaurus (it may actually be a species of the latter). This smaller species is restricted to the deep forests of the Front Range highlands and is recognizable by its smaller plates, more numerous tail spines and a long spike over each shoulder.
ANKYLOSAURS
This family of armoured dinosaurs evolved in the Late Jurassic (although they are ironically named after one of its last members, Anklyosaurus – see below) and there may be two species in the Morrison but possibly more. The two known for certain, Mymoorapelta and Gargoyleosaurus, are roughly similar in size, growing to about 10–15ft in length and weighing about a ton. They differ in the type of armour although both have a paving of armoured scutes on their backs and flattened spikes running down their flanks. They also have armoured heads with small spikes extending from their cheeks and the back of their skulls.
These are hardy animals that will eat any kind of plant matter and even scavenge, should the opportunity present itself; they can also live for extended periods without water. As such, one species seems to live out in the Foredeep, eking out an existence around billabongs and waterholes on the interior during the long Morrison dry season. The other species lives in the thick gallery forests and swamps, living an almost semi-aquatic existence akin to the likes of a forest hog or pygmy hippo.
Rarely seen, little else is known about these dinosaurs.
CAMPTOSAURUS
The most common herbivore of the Morrison, the more widespread and smaller species grows to about 15ft in length and weighs about half a ton. The rarer giant species can measure 25ft and weigh over a ton. Both the lesser and the giant species move in herds; in the case of the former, these can be very large, more than 100 individuals. The giant type travels in smaller groups of five to ten animals. Young often travel with the adults for protection.
Both types have a typical Ornithopod-like build, with a small, beak-tipped head, barrel-shaped body and long neck and tail; they are habitual quadrupeds but semi-bipedal. This enables them to feed along a broader vertical axis. Generally a low-browser and grazer, they can stand to feed higher up if needed; this enables them to expand their diet during the worst of the dry season. The giant Camptosaurus has much longer, more heavily built arms and a thumb spike akin to later Iguanodonts. It will use its greater size and powerful forelimbs to wrestle down small trees and pull up roots and tubers.
Both run only on their hind limbs; this is their main defence against predators. The young are leaner and longer-legged, and therefore quicker. However, the lesser Camptosaurus is a main menu item to just about every medium and large predator in the Morrison, while even small Coelurosaurs will take the young. The giant type is a difficult catch especially with its thumb spike and power.
For the lesser Camptosaurus, safety in numbers is also a useful defence. They not only travel in herds but also nest communally during the wet season out in the Foredeep, the adults protecting the breeding site from all comers. The young spend some time in the nest where they are fed by both parents. Once they are big enough, the young form huge crèches protected by the adults until large enough to leave the parental heard and form their own group; males stay in bachelor herds until they reach breeding age, when they will try to join herds with sexually mature females.
Both species are widely distributed, although the lesser type prefers more open environments; the giant species inhabits open woodland but herds also frequent gallery and riverine forests. The females of both types also change colour during the seasons, adopting more greenish camouflage during the wet season; the males of the lesser Camptosaurus are black with white faces, while the giant males are a more chocolate brown.
A number of small Ornithopods frequent the Morrison. Dryosaurus fulfils the ecological role of the gazelle, small, nimble and often in the company of larger herbivores. Its long hind limbs and tail, plus light build, make it one of the fastest animals in the Morrison. It puts its speed to good use out on the open spaces of the Foredeep, where it browses out on the fern prairies. Small herds of these 8–12ft-long runners are a frequent site out on the plains.
Less obvious are the Nanosaurs, such as Nanosaurus, Drinker and Othnielosaurus. These are, as the name suggests, the smallest dinosaurs of the Morrison. Some, such as Nanosaurus, are rarely seen, inhabiting as they do the deep forests and dense woodlands of the Front Range foothills and lowlands. Others, however, are found out on the Foredeep but remain hidden from sight because they are burrowers. They live in small family groups in dens they dig out. They nest and raise their young beneath the ground, and although generally herbivores, they are quite happy to supple
ment their diets with small amphibians, eggs, insects, worms and other invertebrates.
Several Morrison inhabitants, including a Nanosaurus (in its burrow), a Dryosaurus (left), a pair of Camptosaurs and Camarasaurs. Meanwhile, a small terrestrial croc makes a dash for cover in the foreground.
CONCLUSION
Perhaps second only to Dinosaur Park in the richness of its wildlife, the Morrison also presents the spectacle of some of the largest and greatest animals ever to have walked the Earth. It also offers the opportunity to hunt three exceptional predators in a varied environment, its wide, open spaces making it the ultimate in walking safaris!
CARRION
(Excerpt from Past Tense by Jason Hoelzemann. Used with permission)
I have never been comfortable with heights but I could not help but sit at the edge of the Victor’s cabin, my feet hanging in the air, as the Pink Team lifted us to the campsite.
We overflew a flock of white Rhamphorhynchoids, snowy little kites streaming long ribbon-like tails tipped with a diamond. They stood out bright against the endless plains of the fern prairie, now turned to a sea of green by the new rain.
Watercourses spidered out across the plains like the pewter-coloured veins and arteries of the landscape. Rushes rippled in the breeze.
The wind from the jet wash blew over us. It was the first time I had been cool since I had arrived in the Jurassic. I enjoyed it while I could because the Pink Team was starting its descent.
Miller [the pilot] radioed, ‘Drones have spotted a Theropod, seven klicks north-east.’