How losing a bone in our noses gave us the ability to enjoy flavour | New Scientist

Delicious: The evolution of flavor and how it made us human

Humans need all the help they can get from their senses to stop them making mistakes with their varied diet. Let’s hear it for aroma and flavour that helped make them what they are, say Rob Dunn and Monica Sanchez in their fascinating book Delicious

HOW do we know what to eat? Dolphins need only hunger and a mental image of what food looks like. Their taste receptors broke long ago and they no longer detect anything but salty flavours, thriving on hunger and satisfaction alone.

Omnivores and herbivores, on the other hand, have a more varied diet – and more chance of getting things badly wrong. They are therefore guided by much more highly developed senses of flavour and aroma.

In Delicious, evolutionary biologist Rob Dunn and anthropologist Monica Sanchez weave together what chefs know about the experience of food, what ecologists know about the needs of animals and what evolutionary biologists know about how our senses evolved. Together, this knowledge tells the story of how we have been led by our noses through evolutionary history, turning from chimp-like primate precursors to modern, dinner-obsessed Homo sapiens.

Much of the research described here dovetails neatly with work described in biological anthropologist Richard Wrangham’s 2009 book Catching Fire: How cooking made us human. Wrangham argued that releasing the calories bound up in raw food by cooking it led to a cognitive explosion in H. sapiens around 1.9 million years ago.

As Dunn and Sanchez rightly point out, Wrangham’s book wasn’t short of a speculation or two: there is, after all, no clear evidence of fire-making this far back. Still, they incline very much towards Wrangham’s hypothesis.

“The loss of a bone that helped separate our mouth from our nose had consequences for human olfaction”

There is no firm evidence of hominins fermenting food at this time either – indeed, it is hard to imagine what such evidence would even look like. Nonetheless, the authors believe it took place. They make a convincing, closely argued case for their rather surprising contention that “fermenting a mastodon, mammoth, or a horse so that it remains edible and is not deadly appears to be less challenging than making fire”.

“Flavor is our new hammer,” the authors admit, “and so we are probably whacking some shiny things here that aren’t nails.” It would be all too easy, out of a surfeit of enthusiasm, for them to distort their readers’ impressions of a new and exciting field, tracing the evolution of flavour.

Happily, Dunn and Sanchez are scrupulous in the way they present their evidence and arguments. As primates, our experience of smell and flavour is unusual, in that we experience retronasal aromas – the smells that rise up from our mouths into the backs of our noses. This is because we have lost a long bone, called the transverse lamina, that helps to separate the mouth from the nose.

The loss had important consequences for olfaction, enabling humans to search out tastes and aromas so complex that we have to associate them with memories in order to individually categorise them all.

The story of how H. sapiens developed such a sophisticated palate is also, of course, the story of how it contributed to the extinction of hundreds of the largest, most unusual animals on the planet. Delicious is a charming book, but it does have its melancholy side.

To take one dizzying example, the Clovis people – direct ancestors of roughly 80 per cent of all living Indigenous populations in North and South America – definitely ate mammoths, mastodons, gomphotheres, bison and giant horses. They may also have eaten Jefferson’s ground sloths, giant camels, dire wolves, short-faced bears, flat-headed peccaries, long-nosed peccaries, some tapir species, giant llamas, giant bison, stag moose, shrub-oxen and Harlan’s muskoxen.

“The Clovis menu,” say the authors, “if written on a chalkboard, would be a tally of a lost world.”