Carnotaurus vs Mapusaurus
Rain has returned to the landscape with seasonal storms rolling in. The rivers and streams are full of churning brown water, with sediment and debris washing out of the hills. Cretaceous Patagonia is a harsh landscape, but local dinosaurs are well adapted to the challenges. Herds of sauropods and hadrosaurs graze on the fresh flush of diverse vegetation (Archangelsky et al. 2009) brought on by the rains.
Mapusaurus is not well. The cuts to her neck and shoulders inflicted by her scuffle with Austroraptor have become infected (Molnar 2001). The dust in the area of their battle was full of dried animal droppings, which fostered a bacterial contamination that propagated in her wounds. The skin is red and inflamed, and the flying insects are constantly pestering her, making her jumpy and twitchy. It is hard to sneak up on prey when you have to continually shake off the biting insects. Mapusaurus has not eaten well lately, and it shows in her reduced fitness and energy.
She can smell carrion on the wind however, and has been following the scent through the vegetation. Nearby, Carnotaurus has been feeding off and on all morning on a yearling hadrosaur he managed to catch the previous day. The powerful muscles in his tail allowed him to chase down the young hadrosaur with ease, slashing with his short muscular jaws and powering it to the ground (Therrien et al. 2005).
After having had his fill yesterday, he is continuing to feed from the carcasse, and there is still plenty of good meat left to be consumed. This is a good opportunity to put on weight against any lean times ahead.
Across a gap in the vegetation, he sees some movement, and a large carnivore steps out into the open. It is Mapusaurus, but there is something off about her. As a predator, he is attuned to any injury or illness in the creatures around him, and he can smell and see that the intruder is not in peak condition.
Mapusaurus has found the source of the tantalising carrion smell, but it is not the easy meal she was hoping for. The Carnotaurus in front of her is only a little smaller than she is, and looking well fed at the moment. She takes a few tentative steps towards the carcasse, but Carnotaurus does not move, and does a deliberate tail swing, lifting up his powerful head, showing off his muscles. Mapusaurus stamps and sniffs, edging a little to one side, eyeing the carcasse and its defender. Carnotaurus takes a step forward, staring right back, and another step.
Knowing she is no match at the moment, Mapusaurus turns around and backs off, she is too weak to fight. She must continue looking for an easier meal, and hope that her body can fight off the infection.
Molnar, R. E., 2001, Theropod paleopathology: a literature survey, In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 337-363
Sergio Archangelsky, Viviana Barreda, Mauro G. Passalia, Maria Gandolfo, Mercedes Prámparo, Edgardo Romero, Rubén Cúneo, Alba Zamuner, Ari Iglesias, Magdalena Llorens, Gabriela G. Puebla, Mirta Quattrocchio, Wolfgang Volkheimer. 2009. Early angiosperm diversification: evidence from southern South America. Cretaceous Research, Volume 30, Issue 5, Pages 1073-1082.
Therrien, François; Henderson, Donald; Ruff, Christopher (2005). “Bite Me – Biomechanical Models of Theropod Mandibles and Implications for Feeding Behavior”. In Carpenter, Kenneth (ed.). The carnivorous dinosaurs. Indiana University Press. pp. 179–198, 228.