How can we reconstruct the sense of smell of extinct organisms?

Smell defines so much of animal's life from finding a mate, to tracking down food sources and avoiding predators. Genetics and behaviour can offer us rich insights for modern organisms, but what about extinct organisms? How did they smell and what was their ecology? This week we take an interesting paper that has found evolutionary links between the endocasts of mammal brains and genetic markers for their 'smellability'. The authors explore how we can use this relationship to infer the smelling habits of sabre toothed cats and giant armadillos, and to reconstruct the evolutionary origins of whales. Get sniffing!

This week's paper is "The olfactory bulb endocast as a proxy for mammalian olfaction" by Quentin Martnez and colleagues published in PNAS in December 2025 https://www.pnas.org/doi/10.1073/pnas.2510575122 We also briefing mention another paper about Cambrian critters in the Ediacaran by Li et al https://www.science.org/doi/10.1126/science.adu2291