New insight into how mammal ancestors became warm-blooded

The shapes of the ear canals of mammal ancestors reveal when warm-bloodedness evolved. The study published in Nature demonstrates that mammal ancestors became warm-blooded later than previously thought – nearly 20 million years later-, and that the acquisition of endothermy seems to have occurred very quickly in geological terms, in less than a million years. The international team of scientists, led by London’s Natural History Museum, the University of Lisbon’s Instituto Superior Técnico, the Field Museum in Chicago, and including the University of Witwatersrand, used the ESRF bright X-rays to scan delicate and dense fossils.

Read more on the ESRF website

Image: Comparison of bony labyrinth shape in two examples of warm-blooded (left) and cold-blooded (right) prehistoric mammal ancestors. © Romain David and Ricardo Araújo.

Breakthrough for body heat-powered technologies

One of the biggest challenges for the advancement of wearable devices, embedded to clothing and accessories, which would be capable, for example, of continuously measuring and transmitting vital sign data, is the availability of power without the need for large batteries.

Thermoelectric materials – in which a temperature difference between two points of the material creates an electric current or vice versa – make it possible to obtain the electrical energy used by the device from the temperature difference between the surface of the human body and the ambient air.

The efficiency of these materials is characterized by their figure of merit zT, which is directly proportional to the electrical conductivity and the absolute temperature of the material and inversely proportional to its thermal conductivity. Thus, obtaining new materials with high value for zT at room temperature and low thermal conductivity is a key element for the development of a new generation of wearable devices based on thermoelectric heat recovery.

>Read more on the LNLS website