Why does Sherlock Holmes use a bloodhound to sniff out clues instead of a poodle? According to a study published on the preprint platform bioRxiv, it all comes down to behavior and training rather than the inherent olfactory abilities of the dogs themselves. The research found no evidence to suggest that the sense of smell in certain breeds of pet dogs is superior to others.
Dogs have incredibly sensitive noses, but researchers believe that training and behavior may lead to differences in odor detection abilities among different breeds. Despite this, some caution that more data on dogs and broader genetic analyses are needed to ensure that all breeds' noses are indeed similar.
This yet-to-be-peer-reviewed study challenges the long-held belief that certain working dog breeds, such as German Shepherds, hounds, and Labrador Retrievers, have particularly advanced odor detection abilities compared to other dogs. Instead, researchers suggest that the success of these dogs in odor detection may stem from generations of training within those breeds.
Lead author of the study, functional morphologist Deborah Bird from the University of California, Los Angeles, stated, "Dogs are among the most scent-sensitive mammals, especially in certain breeds where the sense of smell is particularly strong."
Due to the difficulty in testing whether some dogs have exceptional olfactory skills or are just good at following cues, Bird and colleagues examined the odor detection abilities of domestic dogs, wolves, and coyotes by studying their skulls and genetic material. They used CT scans to create 3D models of 104 skulls from 45 different dog breeds, measuring the area of a bone structure called the cribriform plate, which houses olfactory nerves that transmit scent information to the brain. A larger cribriform plate relative to the mammal's size indicates a better sense of smell.
Researchers also investigated genetic parameters that could indicate the olfactory prowess of mammals. They delved into publicly available dog genome records, surveying the genomes of 111 domestic breeds, 27 wolves, and 4 coyotes to determine the number of olfactory detection genes in each animal. Additionally, they examined oral tissue samples from 24 other domestic breeds to identify genes encoding proteins involved in smell.
Based on these measurements, the researchers concluded that domestic dogs may not have as sensitive noses as wolves and coyotes. Domestic dogs include ancient breeds predating modern dog breeding, such as Australian Dingoes and Basenjis, as well as familiar breeds like Spanish Pointers and Corgis.
The researchers did not find genetic or skeletal evidence indicating that the noses of certain domestic dog breeds are superior to others. Instead, they suggest that some dogs' behavioral traits, such as pleasing others or high endurance, make their noses appear more discerning than those of other dogs.
However, this study did not test dogs in the wild. In natural settings, some breeds may excel in search and rescue or drug detection operations due to their endurance, trainability, or ability to please humans.
"We think that some dogs may have better scent abilities than others not necessarily because their noses are exceptional, but because they are interested in using their noses to help us accomplish what we want them to do," said computational biologist Elinor Karlsson from the Broad Institute in the United States.
For more information on the related paper, visit: https://doi.org/10.1101/2024.04.15.589487
