Our ability to detect the characteristic metallic smell left on the skin after handling iron-containing objects like coins and keys may have evolved for a more gory purpose: to help our hunter ancestors track down wounded prey.
Fats on the skin break down to form volatile, strong-smelling substances called ketones and aldehydes when they come into contact with iron – whether it comes from the environment or from haemoglobin in blood – says Dietmar Glindemann, a chemist at Virginia Polytechnic Institute and State University in Blacksburg.
Glindemann and his team identified the chemicals after analysing vapours produced when seven volunteers rubbed metal…
