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Smell, not Smarts, Drove Evolution of Early Mammals' Brains

New paper on evolution shows early mammals' brains dominated by smell center.

In an interesting new paper in the latest issue of Science, paleontologists draw some sweeping conclusions about brain evolution by examining skulls of some 190 million year old creatures on the road to becoming mammals.

It may not have been survival of the smartest but of the keenest sniffers that pushed the brains of early mammals to grow far bigger and more complex than those of their reptilian ancestors.

A group of paleontologists announced Friday that they had used CT scanning to analyze the skulls of ancient creatures on the evolutionary path to becoming mammals, and found most of the brain growth occurred in the smell center - the olfactory bulb.

"We associate the brain's primary function with thinking," said Zhe-Xi Luo, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh, who was part of the team. "But we didn't get our brain for thinking - we got our brain for the more basic and primitive needs."

Smell was primal, while thinking became important much later. Read the rest here.

There wasn't room to include more on way the University of Texas researchers are using CT scanning to get information that previously would have required making a cast and then destroying the original fossil. Paleontologist Tim Rowe told me they've used the machine to examine archaeopteryx(the earliest bird),  Martian meteorites, and even the famous hominid Lucy.

I also had a long and fascinating conversation with neuroanatomist Glenn Northcutt, who said he believes the evolution of warm-bloodedness made new demands on animals - they have to eat seven times as much - and that spurred the evolution of relaively large brains in mammals and birds.

If smell is so important to mammals, what happened to us humans? Why are so such poor sniffers compared to dogs? Find out in Monday's column, to be posted first thing in the morning.