I'm trying to understand how they discovered or speculated the age of Sue the Tyrannosaurus rex to be about 28–29 years old. How do they know exactly the age of Sue? Could it be wrong? Could it be possible that she is older then they thought — maybe 35 years old?


1 Answer 1


Dinosaur bones contain rings, similar to a tree, that can be counted to determine age. SUE was 28 when she died, making her the most geriatric Tyrannosaurus yet found. Her bones show signs of wear and even disease, including arthritis.

Paleontologists can make micron slices of bone and view the rings through polarized light, even on a microscope at 5-10x, similar to geologist mineral ID's.


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Wiki: Growth lines may be deposited in synchrony with endogenous biorhythms. For example, captive crocodilians exposed to constant temperature, diet, and photoperiod, still exhibit the periodic and cyclical skeletal growth banding of their wild counterparts.[4] Consequently, it is assumed by many paleontologists that the growth lines of dinosaurs reflect annual rhythms, and that they may be used to determine individual ages. However, in the large and long bones of many dinosaurian taxa, resorption of internal and external bone proceeds even as new cortical bone continues to be deposited, so that growth lines deposited early in development may need to be inferred.


  • $\begingroup$ though could it mean sue might reach older age if yes how old im hoping 40yrs because most larger birds can reach over 30yrs $\endgroup$
    – Gian
    Jan 30, 2018 at 1:34
  • $\begingroup$ If you read about dinosaur longevity, It says that 29 is a fair old age for a T-Rex because they are related to eagles and ravens which live 20 to 30 years on average. The oldest wild bald eagle lived 38 years. 50 years in captivity. Because it has to hunt very actively, it must be in peak form every month of every year. Crocs can go 60 years but they are cold blooded. Other extinct genera than dinosaurs could manage 60-70 years perhaps. $\endgroup$ Jan 30, 2018 at 4:49
  • $\begingroup$ The oldest wild tiger was 20 and the oldest bear was 39. If the T-Rex had the same health as a bird, at 32 years old, the probability that it can still catch prey with 15 tons to throw around, is slim. Spinosaurus could perhaps live to 40, because it's an agility predator too, same as an eagle, and you can imagine a 40 year old eagle fighting for territory, it would be doomed. $\endgroup$ Jan 30, 2018 at 5:36
  • $\begingroup$ The oldest wild albatross is 67 years old, so perhaps a female Spinosaurus can live twice as long as a t-rex :) en.wikipedia.org/wiki/Wisdom_(albatross) $\endgroup$ Jan 30, 2018 at 5:38
  • $\begingroup$ so trex cant live nearly 35-40yrs $\endgroup$
    – Gian
    Jan 30, 2018 at 23:55

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