Animals can \"focus\" their sense of smell using their noses in much the same way humans focus their eyes to improve vision, U.S. researchers say. Scientists at the University of Chicago studying rats said the animals adjust their sense of smell through sniffing techniques to get scents to receptors in different parts of the nose and changed the sniff patterns based on what kind of substance they were attempting to detect, a university release reported. The sense of smell, often used to detect predators or to search for food, is very important to animals, researchers said. \"Dogs, for instance, are quite dependent on their sense of smell,\" psychology Professor Leslie Kay said. \"But there are many chemicals in the smells they detect, so detecting the one that might be from a predator or an explosive, for instance, is a complex process.\" Researchers have shown animals can use their noses to separate chemicals in complex scent blends based on the rate at which different chemicals are absorbed by mucous in the noses and by changing the speed of air flow through their noses as they sniff. \"The physical properties of the odors matter a lot, and so does the type of sniff that an individual uses to smell the odors,\" study co-author Daniel Rojas-Libano said.