Tarchia

## TarchiaBrainy One

* Adult
* Juveniles

**Tail Club Weight** of 23 kilograms (50 pounds)

 **Main** Segments Gallery

MainSegmentsGallery

***“ Without water, no animal can survive. Yet, this is home to these young Tarchia. They are desert-living ankylosaurs, heavily-armored, with huge, clubbed tails. ”***

― **David Attenborough**, *Badlands*
***Tarchia*** (Brainy One) is a genus of ankylosaurid dinosaur that lived in the Barun Goyot and Nemegt Formations, Mongolia, 75 - 70 million years ago, from the Campanian to the Maastrichtian stage of the Late Cretaceous Period.

The species that was depicted on Prehistoric Planet could be any of the two species which lived in the Nemegt Formation (*T. teresae* and *T. tumanovae*), for the Nemegt Formation is the likely setting of the segments the species appears in (the type species, *T. kielanae*, lived in the earlier Barun Goyot Formation, and also possesses some differences in skull features). Given the time the show was worked on, however, it is likely that the species shown is *T. teresae*, since *T. tumanovae* was only set as a new species in 2021, when the show was already being worked on.

## Paleobiology

### Size, Physique, and Armor

***“ In the end, the Prenocephale are little more than annoying. But an adult Tarchia is another matter, especially one almost twice the youngster's weight. It wields a club weighing almost 50 pounds. ”***

― **David Attenborough**, *Badlands*
A large ankylosaur around 5.8 - 6.7 meters (19 - 22 feet) long and 2.5 metric tons (2.8 short tons) in weight, *Tarchia* is depicted with the standard ankylosaur body, heavily-armored with osteoderms set in thick skin and equipped with a massive tail club. This club, as stated on the show and justified in the Uncovered segment dedicated to discussing the purpose of ankylosaur tail clubs, can weigh around 23 kilograms (50 pounds) in adults, good for fighting off predators and each other, with evidence being seen on one *Tarchia* specimen with pelvic and tail injuries as well as an asymmetrically-shaped club, likely worn down by several strikes. On Prehistoric Planet, traces of this can be seen on the adult *Tarchia*, which has the tip of one of the spikes on its back chipped off, likely due to having gotten involved in such conflict previously. It also shows his experience, and why he is willing to intimidate and take on a juvenile that trespassed into his domain, and wisely backed off when another juvenile *Tarchia* came, doubling the threat of getting clobbered by tail clubs.

### Desert Life Adaptations

***“ Dark patches protect the Tarchias' eyes from the glaring sun. And this is the sound of Tarchia's very own air-conditioning system. Their large nose cools the air as it leaves the body, condensing - and so conserving - valuable water with every breath. It allows them to survive long periods without drinking as they search for a meal. ”***

― **David Attenborough**, *Badlands*
Despite all these defensive features, given how they live in the desert, which could be the biggest enemy of all creatures within it, all this heavy armor isn't enough, hence why they are also shown with adaptations to survive the intense heat. Prehistoric Planet depicts *Tarchia* with dark patches to protect their eyes from the sunn. One key to their survival is their large nose, considered as "*Tarchia's* very own air-conditioning system", meant to conserve the water they have whenever they breathe. As for the internal features of their head, *Tarchia* got its name, "brainy one", since, given how large the base of its skull is, it is presumed to have a larger brain than *Saichania*, a closely-related ankylosaur that lived in the same area and the same time, with this difference in brain size believed to be one way to distinguish both ankylosaurs from one another.

As a desert-dwelling species, *Tarchia* needed all the nutrition it can get. Hence, they are seen subsisting on even low-quality plants in the desert, and, as indicated by their muzzle, broad and rectangular, they relied on bulk feeding, consuming all that they can. *Tarchia* also likely processed food in the gut rather than the mouth (so it may have preferred to feed on succulent plants that do not require complex chewing), and microwear pits imply that it had to deal with more grit compared to ankylosaurs that lived in tropical environments since it lives in the desert.

### Growth

The growth cycle of *Tarchia* is unknown. However, based on *Pinacosaurus*, an earlier ankylosaur from Mongolia and China, *Tarchia* may have grown to at least 60% of their adult size without reaching sexual maturity yet. An adult *Pinacosaurus* is around 5 meters (16 feet) in length, while the holotype specimen is only 3 meters (10 feet) long, still considered a juvenile due to some bones either being fewer in number or still being fused (four of their rear dorsal vertebrae are fused into a "sacral rod"). As they grew, the forelimbs of juvenile ankylosaurs become more robust, while their hindlimbs do not become significantly larger relative to the rest of the body. The process of ossification (the formation of bone, as well as the conversion of some preexisting parts into bone) then proceeds from the snout and the neck all the way down to the tail.

On the show, the two juvenile *Tarchia* are about half the size of the adult they encounter, but they proved themselves to be large and strong enough to intimidate small animals like *Prenocephale* and, together, even threaten an adult *Tarchia*, which, having recognized their chances of beating him, promptly backed away from them.

### Prehistoric Planet's Depiction

*Main: *Tarchia* on Prehistoric Planet*

Main: *Tarchia* on Prehistoric Planet

***“ Trudging through a scorching desert, two young Tarchia find relief at an oasis and encounter an adult twice their size, ready to lay claim. ”***

― The official Apple TV+ episode synopsis for *Badlands*
Prehistoric Planet depicts *Tarchia* as being mostly brown, very much like the usual coloring associated with ankylosaurs. This dark coloration is explained on the show as a means of protecting them from the heat of the desert sun. Their armor also comes in the form of prominent spines rather than simple pebbly knobs and studs.

A few *Tarchia* briefly appear among the animals that visit the temporary oasis in the fourth segment of Deserts. The species would end up becoming the main characters of the fourth segment of Badlands, where two young *Tarchia* journey through the desert and find a small spring in a canyon, running afoul of the canyon's residents, a group of seven *Prenocephale* and an adult *Tarchia* twice their size. *Tarchia* and other club-tailed ankylosaurids would also become the focus of the Prehistoric Planet: Uncovered segment "How Did Ankylosaurs Use Their Tail?", where it is determined that ankylosaurs used their clubs not only for defense, but also intraspecific combat, with research regarding the ankylosaur *Zuul crurivastator* being one likely support for the information brought up during that segment.

## Paleoecology

### Paleoenvironment

*Main: Nemegt Formation*

Main: Nemegt Formation

***“ The high temperatures here create scouring winds which carve the rocks into extraordinary shapes. But they also strip the ground of soil. Some plants, however, manage to take root in cracks between the rocks. Any meager mouthful is worth competing for. ”***

― **David Attenborough**, *Badlands*
*Tarchia* lived in a place that would eventually become the Gobi Desert of Mongolia. The type species, *T. kielanae*, lived 72 million years ago, when the region, based on evidence of the environment preserved in the Barun Goyot Formation, was an area of sparse vegetation, sand dunes, and rocks heavily eroded by strong winds. Even so, small, intermittent lakes and seasonal streams can still form in this desolate region. Two million years later, during the time of later *Tarchia* species, *T. teresae* and *T. tumanovae*, the area became an overall more hospitable area, and, based on evidence of the environment preserved in the Nemegt Formation, the desert was replaced by a rich, humid environment with large river channels, tidal flats, and forests.

Even so, the area is also known to have undergone periodic droughts, and there is precedence for arid regions much like the Gobi Desert today existing in Mongolia during those times, with the only compensation coming in the form of oases, as seen in the fourth segment of Deserts when a few *Tarchia* and other animals visit a temporary oasis. This is also shown on the fourth segment of Badlands, when the juvenile *Tarchia* came across a small spring within a canyon in the middle of the desert.

### Paleofauna

*Tarchia* coexisted with animals smaller than it, like *Mononykus*, *Prenocephale*, and velociraptorine dromaeosaurs, though it itself is dwarfed by other even larger animals, like *Barsboldia*, *Deinocheirus*, *Therizinosaurus*, *Nemegtosaurus*, *Opisthocoelicaudia*, and massive titanosaurs that possibly rival *Argentinosaurus*. *Tarchia* also lived alongside the similarly-sized ankylosaur *Saichania*, with the two species able to coexist due to niche partitioning (though what niche each species occupied is still unclear). Despite its armor and bone-shattering tail club able to keep it safe from most hunters, *Tarchia* was not immune from predation. A *Tarchia* skull was found with the tooth marks of the tyrannosaurid *Tarbosaurus*, the apex predator of the Nemegt Formation. While it is possible that this was the result of scavenging, it is likely that the tyrannosaur used its five-ton bite force to kill the ankylosaur.

### Navigation

***“ Like many nomads, the Tarchia have a mental map of the desert, and can travel across empty landscapes with unerring accuracy. They remember the rare places where there are natural springs. Desert oases, like this one. A life-saver for animals that can find them. ”***

― **David Attenborough**, *Badlands*
Much like *Secernosaurus*, *Tarchia* are depicted as being able to make their way through the desert via some means. In this case, the juveniles either remember the location of the spring due to a prior memory (indicating that, even as young animals, they are already well-traveled), or are simply able to sense where oases are based on telltale signs of places that can likely have water, like the presence of plants, presence of other animals, or the area itself simply looking like it could retain or even hide water better than others, like an isolated canyon.

### Social Habits

***“ If this comes to a fight, the juvenile can't win... but reinforcements are on the way. ”***

― **David Attenborough**, *Badlands*
The social habits of *Tarchia* are not well-known. But based on *Pinacosaurus*, its more ancient relative from Mongolia and China, *Tarchia* may have lived in groups as juveniles, but eventually split and live solitary lives as adults. At least 24 juvenile *Pinacosaurus* have been found buried alive, possibly due to a sandstorm, while adults have not been found in such groups. On Prehistoric Planet, only two young *Tarchia* are shown traveling together, and, while they are initially shown competing for resources initially, in the end, their companionship allowed them to successfully threaten a lone adult *Tarchia* twice their size. This strategy of youngsters traveling together independent of adult care was also seen in various animals depicted on the show, from *Alcione*, *Antarctopelta*, and *Therizinosaurus*, to *Zalmoxes*, *Isisaurus*, and *Nostoceras*.

### Competitive Habits and Agonistic Behavior

***“ Tensions often run high around an oasis. But a display of strength can prevent a dangerous battle. ”***

― **David Attenborough**, *Badlands*
Given how resources are limited in the desert, animals may be justifiably greedy and competitive over resources. Within the show, the *Tarchia* showcase this when one refused to share a patch of vegetation with his companion, shoving him away when he tried to get close. Following this, the other juvenile *Tarchia* intimidated a group of *Prenocephale* into leaving him alone and letting him have the oasis to himself by slamming his club down on the ground. Upon encountering an adult *Tarchia* almost twice his weight, both the juvenile and the adult fight over the oasis, even though the younger individual is clearly outmatched, though this changed when the other juvenile *Tarchia* came in, and together, both intimidated the adult into letting them also have a share of the oasis.

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## References

1. ↑ 1.0 1.1 As stated in Badlands.
2. ↑ 2.0 2.1 A new ankylosaurid from the Upper Cretaceous Nemegt Formation of Mongolia and implications for paleoecology of armoured dinosaurs
3. ↑ Diversity and convergences in the evolution of feeding adaptations in ankylosaurs (Dinosauria: Ornithischia)
4. ↑ Martin, A. J. (2006). *Introduction to the Study of Dinosaurs* (2nd ed.). Oxford: Blackwell Publishing. p. 560.
5. ↑ Postcrania of juvenile *Pinacosaurus grangeri* (Ornithischia: Ankylosauria) from the Upper Cretaceous Alagteeg Formation, Alag Teeg, Mongolia: implications for ontogenetic allometry in ankylosaurs
6. ↑ Hands, Feet, and Behaviour in Pinacosaurus (Dinosauria: Ankylosauridae)
7. ↑ Palaeopathological evidence for intraspecific combat in ankylosaurid dinosaurs
8. ↑ Gallagher W.B., Tumanova T.A., Dodson P., Axel L., 1998, "CT scanning Asian ankylosaurs: paleopathology in a *Tarchia* skull", *Journal of Vertebrate Paleontology* **18**: 44A-45A
9. ↑ Two new dinosaurian reptiles from Mongolia with notes on some fragmentary specimens. *American Museum Novitates*