Olorotitan vs TherizinosaurUs

70 million years ago in Late Cretaceous Mongolia, dense forests interspersed between river channels, with tall conifers forming the canopy, and diverse assemblages of leafy understory plants filling the lower strata. These understory plants are beginning to look rather brown and brittle, as rain has not fallen for a couple of weeks. Dark clouds are gathering on the horizon, and a stiff wind blows a small storm over the forest. 

The storm passes over quickly, but not before a crack of lightning starts a surface fire in the ready tinder of the understory. The fire grows as the rain subsides, burning through the dry underbrush, and spreading quickly. The flames devour that which is without moisture and clears the low vegetation as it goes. The fire is picking up stream, licking at the low branches of the conifer trees and threatening to spread into the canopy. Fortunately, a larger storm, blown in on the same wind that brought the last, dowses the landscape in a torrential downpour. After 48 hours of straight rain, the fire is quenched. The understory is bare, but the canopy has survived with only some minor scorching. 

Therizinosaurus roams back into his home environment. The fire had forced him to flee out onto the open river flats to escape the blaze, but with the danger extinguished he is free to return to the relative safety of his preferred forest habitat. Though he has eaten well all summer, Therizinosaurus has been kept from foraging by his displacement and is now hungry. He heads towards the tree line in hopes of finding some tasty foliage that hasn’t been reduced to ash. 

Olorotitan, arriving from a vast wetland in late Cretaceous eastern Russia, looks upon the post fire landscape with much greater dismay. She has just narrowly escaped being swept away by flood waters in her home environment, and now the disruption to her foraging seems a more serious concern than the minor inconvenience it was before. Picking her way between partially blackened trunks, she searches for any surviving pocket of the horsetails and low-level leafy vegetation upon which she usually depends (Williams et al.). Finding nothing, she raises upon hind legs, stretching towards the tantalizingly green branches of the unburnt canopy above. Though she is a full 8 meters from nose to tail, and possesses an unusually long neck for a hadrosaur, the branches remain frustratingly out of reach. 

While Olorotitan searches fruitlessly for food, Therizinosaurus is taking advantage of his natural gifts to great success. At 10 meters in height, with a vertically oriented body position and a reach extended by its impressively long claws, he is able to reach far above the browsing height of his contemporary herbivores (Phil & James) Pulling branches down from above the fire damage, Therizinosaurus is eating well. 

Drawn by the sound of shaking branches, Olortitan catches sight of Therizinosaurus through the trees. The giant is pulling down branches and stripping the foliage. Some of these branches break off from the tree and fall to the ground at Therizinosaurus’s feet. If Olorotitan can get close enough, the remaining foliage on the downed branches might be enough to stave off hunger. 

Olorititan approaches Therizinosaurus, head lowered and feet stamping. This position puts its colorful crest of display, and through it Olorotitan emits a loud bugle. She is hoping to push Therizinosaurus to abandon his position in favor of a foraging spot without competition. Though capable of defending himself against potential predators, this gentle giant is not among the most aggressive in terms of territory defense. 

Unfortunately for Olorotitan, Therizinosaurus is in no mood to suffer competition. As the hadrosaur encroaches into his space, the therizinosaurid swipes out low with his claws. Olorotitan dances backwards, prepared to retreat in the face of a larger competitor. Not fast enough. Therizinosaurus’s claws catch on Olorititan’s shoulder, leaving long, thin gashes. Surprised by the aggression more than the pain, Olorotitan continues to skitter back and away. Therizinosaurus watches her retreat warily until she disappears into the trees, then returns to his foraging.

Just out of sight, Olorotitan lies low to give her wounds a chance to heal. She will wait until Therizinosaurus has moved on before returning to see what foliage might have been left behind. Better safe than sorry.

Therizinosaurus advanCes!!!



Williams, V. S., Barrett, P. M., & Purnell, M. A. (2009). Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding. Proceedings of the National Academy of Sciences106(27), 11194-11199.


Phil, S. E. N. T. E. R., & James, R. H. (2010). Hip heights of the gigantic theropod dinosaurs Deinocheirus mirificus and Therizinosaurus cheloniformis, and implications for museum mounting and paleoecology. Bull. Gunma Mus. Natu. Hist, 814, 1-10.


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