Large animals like T. rex would have had to adopt energy-efficient postures to conserve energy. Research suggests that T. rex might have moved with straight legs, similar to elephants, to reduce the energy expenditure associated with bent legs. This posture would have helped in distributing the weight more efficiently, reducing the strain on muscles and bones. And studies have shown that Tyrannosaurus rex was not capable of running at high speeds due to biomechanical constraints. For instance, a biomechanical model suggests that a 6,000-kilogram T. rex could not have packed enough muscle into its legs to hustle faster than about 40 km/h. This limitation is further supported by research indicating that true running gaits would lead to unacceptably high skeletal loads in T. rex, mechanically limiting it to walking gaits. I wonder what other issues that sheer size would inevitably bring. Wouldn't they be massive vessels for all sorts of parasites and viruses and what not as well?