How do you take the temperature of an extinct animal?

The ability of an animal to influence its body temperature is a vital process. It influences how fast metabolic reactions can occur, how fast muscles fibers fire, and over all how ‘active’ an animal can be. There are multiple techniques that can be used to measure the body temperature and metabolic activity of a living animal, but how do you measure the body temperature of an animal that’s been dead for over 66 million years? Follow along as we explore a few analytical methods that shed light on the internal temperature of the dinosaurs.

Fig 1. Cast of Tyrannosaurus rex “Scotty” located at the Houston museum of natural science
Fig 1. Cast of Tyrannosaurus rex “Scotty” located at the Houston museum of natural science

Introduction/ Background

Since their initial discovery in the early 19th century, our understanding of the non-avian dinosaurs (hereafter refered to as dinosaurs) has changed radically. New specimens and methodologies have elucidated evolutionary relationships, as well as aspects of their anatomy, ecology and behaviour. One frontier that the scientific community is making marked progress on is in uncovering much of physiology behind these extinct animals. While their physiological processes are admittedly difficult to study due to the general lack of soft tissue preservation in fossils, and the obvious lack of living specimens, certain features of there physiology are still within reach after several million years.

One of the most tantalizing topics in dinosaur physiology is what the thermoregulatory profiles of these animals were. Were the dinosaurs endothermic (warm-blooded) like their modern descendants: the birds? Or were they ectothermic (cold-blooded) like their next closest living relatives, the crocodilians? This area of research picked up steam following the beginning of the “dinosaur renaissance” of the late 1960’s. At this time, several lines of evidence began converging on the notion that dinosaurs were not the lethargic evolutionary dead-ends they had been depicted as since their initial discovery, but were instead more lively, active animals that were still in their prime towards the end of the Mesozoic.

Method #1 Stable Isotope Analysis (a molecular thermometer)

Use data from Dawson et al. 2020 and Flores et al. 2026 (anchor article) to produce a linear model and anova respectively

Method #2 Soft Tissue Osteological Correlates (what can be inferred from bone)

Use data from Allan et al. 2014 to produce a linear model

Method #3 Modelling Metabolism

Use data from Gradt et al. 2014 to produce a linear model and Myhrvold 2015 for further elaboration