Enhanced olfactory performance in deaf Dalmatians: evidence for neurosensory compensation?

Congenital deafness in dogs arises early in life and may lead to compensatory neuroplastic changes involving other sensory modalities. This study assessed whether deaf dogs exhibit enhanced olfactory performance compared to their hearing counterparts. A food search task conducted in a complex indoor environment was used to evaluate olfactory ability. Dogs were required to locate a single hidden kibble across progressively challenging hiding locations. After a learning phase, the evaluation focused on the most difficult conditions, where the kibble was neither visible nor accessible without olfactory guidance. Six purebred Dalmatians (three deaf, three hearing) were initially enrolled; two were excluded due to dropout or lack of motivation. All remaining dogs completed six training sessions before evaluation. Performance was measured as search speed (distance divided by search time), and group differences were analyzed using linear mixed-effects models. Deaf dogs demonstrated significantly higher search speeds than hearing dogs under the most demanding conditions (kibble hidden at a height), but not under simpler ones. No significant effect of time since last meal or interval between sessions was observed. These preliminary findings suggest a potential enhancement of olfactory performance in deaf dogs, possibly as a compensatory response to early auditory deprivation.