Is T. rex sense of Smell proof of a Bacterial Bite?
By measuring the volume of the brain case of dinosaurs we can estimate the size of their brains. A Tyrannosaurus rex specimen such as BHI3033, “Stan” the nearly complete gracile Tyrannosaurus rex discovered by Stan Sacrison in 1992, had a brain case with a volume of approximately 1,000 cubic centimetres. In contrast, human being’s brains take up a volume of up to 1,800 cubic centimetres. But brain size is not the be all and end all.
Firstly, not all of the brain case volume was made up of brain, there are variations in the percentage of the brain case volume that the actual brain filled. Also, different parts of the brain are responsible for different functions. With T. rex the cerebrum area (the part of the brain dedicated to thinking and problem solving) was very small. In us, this part of the brain makes up by far the largest proportion of brain volume. By looking at the brain case and studying the holes in the skull that carried nerves back and forth we can assess how intelligent a dinosaur was and how much of the brain was dedicated to functions such as sight, thinking, smell, balance and so on.
Scientists have estimated that about 50% of T. rex’s brain was dedicated to sense of smell (olfactory bulb), so it is fair to assume that the sense of smell was very important to Tyrannosaurus rex. Perhaps this helps reinforce the “bacterial bite” theory.
T. rex could ambush an unsuspecting Hadrosaur, inflict a wound with its massive jaws and then use its sense of smell to track down its victim. The T. rex could follow the duck-billed dinosaur for several days, slowly but surely loss of blood and the inflected wound would weaken the animal and then T. rex could step in to finish it off.
Perhaps the large part of the brain dedicated to sense of smell is evidence of a bacterial bite in Tyrannosaurs.
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