Torvosaurus vs. Yutyrannus

Time Period & Environment: West-central North America, 150 million years ago

Written By: Kaitlin Lindblad

Evening in west-central North America, 150 million years ago. A small cloud of volcanic ash drifts in, erupted from the Nevadan Orogeny forming to the west. As the sky turns brilliant red and orange, a colossal splash echoes through the trees. The body of a diplodocid sauropod lies on the shore of a small lake. Weakened by a severe respiratory infection (Woodruff et al. 2022), it has stuck around the watering hole ever since its herd abandoned it about a week ago. The light haze in the air proved to be the last straw.

A resident Allosaurus and a lost Yutyrannus appear from opposing sides, eager to secure their spot for the evening buffet. After a short cautious bellow from the Allosaurus, he tolerates the large feathery early tyrannosaur. Perhaps they share enough similarities, whether it be in their body plans or the brightly coloured hornlets adorned above their eyes. Most likely, there is simply plenty of sauropod to go around.

The activity wakes an old and hardened Torvosaurus. Like the other two predators, she has been watching the sick sauropod with anticipation. With night slowly approaching, she makes her presence known. At close to 10 meters nose to tail, Torvosaurus is the largest of the three. She is greeted with fierce hissing from both parties: no one wants to give up the free sauropod steak.

Torvosaurus turns her attention to the silhouette of the smaller, shaggy predator to the left. The feathered tyrant remains steadfast. Her golden-brown mane of quills rises, and her jaws open farther and farther with each step the intruder makes. Yutyrannus strikes first, snapping dozens of sharp teeth into Torvosaurus’ snout.

Torvosaurus thrashes wildly, strafing a claw well into her opponents’ plumage. Both theropods stumble back, pause, and then collide with even more fury. Landing her jaws on the throat of the tyrannosaur, the greater mass of the Torvosaurus drives the impact. Her opponent careens over the neck of the fallen sauropod and into the drink.

Torvosaurus surveys the faintly glistening water. The ripples soon calm. Silence follows.

In the last of the daylight, Torvosaurus tucks into her share. The Allosaurus, a bystander to the whole brawl and wary of the same fate, shuffles to the opposite side of the sauropod.

Torvosaurus advances!!!


Woodruff, D.C., Wolff, E.D.S., Wedel, M.J. et al. The first occurrence of an avian-style respiratory infection in a non-avian dinosaur. Sci Rep 12, 1954 (2022).

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