Cat's out the bag! Their sense of smell mirrors advanced chemical analysis

Different chemical components interact uniquely along the tube's length, allowing for their identification. While similarities between gas chromatography and nose function have been observed in amphibians, limited research has explored these parallels in mammalian noses, which possess intricate air passages for odor detection.

Zhenxing Wu and colleagues from Ohio State University shed new light by creating a precise 3D computational model of a domestic cat's nose. The model was developed using a combination of techniques, such as high-resolution micro-CT (micro-computed tomography) scans of a real cat's nose and computational fluid dynamics modeling.

Simulation of air and odor flow through the virtual cat nose revealed a striking resemblance to a parallel coiled gas chromatograph, in which the efficiency of the basic technique is boosted by the use of multiple tubes branching off of one high-speed gas stream.

Simply put, if it had only one straight tube for this purpose, it would need to be longer than its head allows. However, cats have evolved with multiple complex channels in their noses, making their odor detection 100 times more efficient compared to amphibians that have a single straight tube. 

Ultimately, the evolution of more convoluted nasal channels in cats has enabled them to excel in precisely and effectively sniffing scents. 

"The evolutionary occurrence of the convoluted olfactory turbinate channels in mammalian noses, remarkably resembles a different sensory organ, the snail-like coiled cochlea that is also unique to mammals," added the authors in a press release.

The theory surrounding cochlea and 'olfactory cochlea'

They highlighted an interesting fact about the inner hearing organ of birds and other non-mammalian vertebrates; this organ, known as the "cochlea," is a blind-ended tube in these animals. 

In contrast, in mammals like us, the cochlea is crucial in enhancing our hearing sensitivity and range of frequencies. 

Building on this knowledge, the researchers believe that a similar structure, called the "olfactory cochlea (i.e., the parallel coiled chromatograph)," may exist in mammals and contribute to our enhanced sense of smell.

"The finding reveals novel mechanisms to support high olfactory performance, furthering our understanding of the successful adaptation of mammalian species, including the cat, an important pet, to diverse environments," they concluded. 

The complete study was published in PLOS Computational Biology and can be found here.