Australia: The Land Where Time Began
The known fossil remains of T. rex include a number of skulls and skeletons, a few juveniles and skin patches.
Compared to other tyrannosaurids the skull was constructed much more heavily and was stouter. To accommodate the oversized muscles of the jaw and neck, the back of the skull is especially broad, this applied to all ages including the juveniles. It had the most powerful bite of any known terrestrial predator.
Norman2 mentions a study of a 2.5 litre coprolite found in Saskatchewan that was found to contain bone fragments around the outer part and bone powder throughout.
Karen Chin, a coprolite specialist from the USGS and her colleagues discovered a coprolite dated to the Maastrichtian, the latest part of the Cretaceous, in Saskatchewan in 1998. The coprolite was more than 40 cm long and had a volume of about 2.5 litres. They noted fragments of broken bone immediately around the inside of the specimen and a sand-like bone powder throughout the mass. It was confirmed by chemical analysis to contain high concentrations of bone material. The material was confirmed by histological thin sections to contain cellular bone structures and that the prey items that were mostly likely present were dinosaurs suggesting the animal that produced the coprolite was most likely a large carnivore. When the fauna known from the area were surveyed it was found that only animal large enough to pass such a large mass in the area was T. rex. When the bone fragments were studied it was concluded that the animal had been able to pulverise the bone in its mouth. Based on the structure of the bone in the histological sections Chin suspects the prey was probably a juvenile ceratopsian ornithischian. As part of the bone had not been digested Norman suggests the carnivore, T. rex was possibly an endotherm.
According to the author3 the eyes were 4 inches in diameter. In front of the eyes the snout had been scalloped out to allow better vision straight ahead. Computer modeling of the skull demonstrates 2 wide cones of vision overlapping in the middle to allow binocular vision and on both sides, wide peripheral vision and there was also a large optic nerve entering the brain.
The arrangement of some hollow bones in the skull leading to the inner ear suggest its hearing was very good at low frequencies - infrasound, sounds not heard by humans, though it is used by elephants to keep in touch over many kilometres. Elephants also use infrasound to warn other elephants by stamping their feet on the ground that sends the low frequency sound more than 30 km. These sound are transmitted up the legs of all elephants in range where it is transmitted to the inner ear.
Infrasound is also used by male crocodilians to threaten other males and to attract females. In the everglades male alligators mistook the ultra low frequency sounds emitted by the space shuttle taking off for other males that responded with their own infrasound communication.
In T. rex the olfactory lobes are very large, similar to that seen in blood hounds but much larger area for reception. The author3 carried out an experiment with bloodhounds which demonstrated that they continued tracking the scent of the person (prey) while ignoring the person they were following even when he ran past them. It appear that if tyrannosaurs were very good at tracking scent trails they were probably used this sense to find prey as well as dead animals.
'Sue' the T. rex has been studied in great detail by Dr. Phil Manning using various scans to gain as much information about the bones to find out more about this dinosaur. 'Sue', the largest T. rex found to date had suffered a number of injuries during her life. She had 2 tail vertebrae that had been broken, then repaired by being covered with bony struts.
|Author: M.H.Monroe Email: firstname.lastname@example.org Sources & Further reading|