Why Dogs and Cats Hear a Wider Range of Sounds Than Humans and the Nose Map Driving Olfactory Research

In this Science Friday episode, Flora Lichtman and Paul explore why dogs and cats hear a wider range of frequencies than humans and what that means for pets and their owners. Dr. Pete Scheifele explains how outer hair cells and ear structure contribute to high frequency sensitivity, and the discussion covers noise induced hearing loss in pets and examples from elephants and dolphins that reveal the diversity of hearing across species. The segment on olfaction features Dr. Bob Datta describing a mouse smell map and the idea that smells may be spatially organized in the nose much like frequency is organized in the ear. The conversation highlights potential implications for treating smell loss in humans and for designing devices that interact with the nose.

• Dogs and cats hear from about 30 Hz up to 57 kHz, far beyond human hearing which tops out near 20 kHz.
• Hair cells in the ear play a key role in detecting high frequencies, illustrating how the ear has evolved for different species needs.
• Public and pet-related noise can cause noise induced hearing loss in dogs and cats, underscoring the importance of managing sound in homes with pets.
• Elephants use seismic rumble that travels through the ground to communicate over long distances, while dolphins hear underwater where sound propagation differs from air.
• Scientists are mapping smells in the nose in a way that echoes the spatial maps found in hearing and vision, with potential applications for treating smell loss.

Overview and Questions

The podcast opens with a practical question from a listener about why dogs and cats hear a wider range of frequencies than humans. Flora Lichtman and Paul pose this question to Dr. Pete Scheifele, a neuroaudiologist at the University of Cincinnati and the executive director of the Fetch Lab, an animal audiology clinic and research lab. The discussion establishes a theme that hearing is not only about the ear but also about how the brain processes sound, and it invites comparisons across species to illuminate how auditory systems adapt to ecological needs.

Frequency Range and the Role of Hair Cells

The conversation confirms the basic frequency ranges: humans typically hear from about 20 Hz to 20 kHz, while dogs can hear down to around 30 Hz and up to as high as 57 kHz, with cats also extending into higher frequencies. Dr. Scheifele explains that the ability to detect these higher frequencies is tied to structural differences in the ear, notably the outer hair cells. Over evolutionary time, the ear has changed to accommodate the demands of a given species, and in dogs and cats the hair cells are key to detecting frequencies outside the human range. The discussion touches on how these differences may influence sounds that animals naturally respond to, such as high-frequency cues used in prey detection or communication.

Evolutionary Perspectives on Hearing

The expert draws comparisons with other species, such as bats that rely on very high frequencies to detect tiny prey like mosquitoes. This contrast highlights how auditory evolution aligns with ecological needs, including food acquisition and navigation. While bats operate at frequencies that humans cannot hear, dogs and cats have evolved a broader high-frequency sensitivity that enables them to discern subtle cues in their environment. The segment underscores that ear structure, hair cell abundance, and neural processing together shape what an animal can hear.

Public Noise and Pet Hearing Health

The discussion moves to public and household noise and its impact on pets. Dogs and cats can experience noise induced hearing loss much like humans if exposed to loud environments for extended periods. The Fetch Lab sees puppies for congenital deafness and works with special operations and homeland security dogs, illustrating a spectrum of hearing health concerns in animals. The conversation also notes breed-related predispositions to congenital deafness, such as in Dalmatians, emphasizing the genetic underpinnings of pet hearing.

Extraordinary Auditory Abilities in the Animal Kingdom

The guest elaborates on elephants, whose rumbles travel through the ground as seismic frequencies and can be detected over large distances, allowing individuals to infer who is making the sound. Dolphins and beluga whales illustrate how aquatic life has adapted its auditory system to sound propagation in water, where sound travels five times faster than in air and shapes both perception and neural processing. The segment clarifies that the brain and ear have adapted to the medium of transmission, leading to a remarkable diversity in hearing across taxa.

Meet the Scientist and the Lab

Dr. Pete Scheifele is introduced as a neuroaudiologist and the executive director of Fetch Lab, described as a one of a kind facility where animal audiology is studied and applied. The discussion ends this portion with appreciation for the lab and its work and signals how animal hearing research can inform our broader understanding of sensory biology.

Olfaction: A Second Sensory Journey

The second half of the episode shifts to the sense of smell with Dr. Bob Datta, a neurobiologist at Harvard Medical School. The conversation centers on a pioneering smell map of the nose in a mouse model. The host and Datta discuss how smell is organized in space, contrasting it with the orderly topographic maps found in the ear and retina. They describe the anatomy of the nose, turbinates and the complexity of the olfactory epithelium, which houses about a thousand receptor types in mice and roughly 400 in humans. The older view that olfactory receptor genes were expressed randomly by olfactory neurons is challenged by modern techniques that reveal a highly organized pattern of receptor expression that forms stripes across the nasal epithelium. This map appears to be largely invariant from one animal to another, suggesting an underlying developmental logic the nervous system uses to construct this molecular machinery.

What the Map Might Mean and Its Applications

The potential significance of the smell map is discussed in terms of what it might reveal about odor qualities and their spatial organization in the nose. The researchers consider whether scent characteristics such as pleasantness might be spatially encoded or whether receptor organization relates to molecular features. They acknowledge that predicting smell from chemistry remains a difficult problem, with recent advances in artificial intelligence improving our ability to predict odor, yet revealing that pleasant and unpleasant odors can share similar chemical features. The map is potentially transformative for therapies aimed at restoring olfaction after loss due to injury or disease, guiding efforts to rebuild the olfactory epithelium and to design devices that stimulate the nose in a map-respecting way. The podcast closes with a reminder that, although the smell map exists in mice, researchers are actively examining whether a similar organization exists in humans and what constraints such a map would place on future treatments.

Significance and Future Directions

Across both segments, the podcast emphasizes the importance of understanding how sensory systems are organized and how this organization constrains therapeutic strategies. For hearing, the differences in ear structure across species illustrate how sensory perception is tuned to ecological demands. For olfaction, the discovery of a receptor map invites new questions about how odors are represented in the nose and how this representation could shape interventions for smell disorders. The episode communicates a broader scientific theme: insights from animal sensing can illuminate human biology and drive the development of technology that respects the underlying organization of our senses.