The technique consists of measuring the concentration of two heavy isotopes: carbon-13 and oxygen-18 . At high temperatures, the distribution of these isotopes is more random. At low temperatures, on the contrary, they clump together. In living creatures, this can be seen in bioapatite , a mineral that is part of bones, tooth enamel, and other hard structures. In this way, by measuring isotopes in the laboratory, it is possible to know the body temperature of an animal with a precision of only 1-2 degrees of error, as Eagle and his colleagues have been able to verify by testing live animals and comparing the data obtained with what the mercury thermometer read.
With the new " paleothermometer ", the scientists announce that more data will be available on the physiology of large reptiles , as well as the changes that took place in some key stages of evolution, such as the appearance of the first birds.
