How do mice use ultrasound? - briefly
Mice emit ultrasonic vocalizations to convey social signals such as aggression, courtship, and distress, and they also detect high‑frequency sounds to locate predators and navigate their environment. These high‑frequency communications travel short distances and are processed by specialized auditory receptors tuned to frequencies above human hearing.
How do mice use ultrasound? - in detail
Mice generate ultrasonic vocalizations through rapid vibrations of the laryngeal membranes, producing frequencies typically between 30 kHz and 110 kHz. The sound pressure levels reach up to 90 dB SPL at a distance of one centimeter, allowing effective transmission in dense, cluttered environments.
These high‑frequency calls serve several functional domains:
- Social interaction – pups emit distress calls when separated from the dam; adults use complex sequences during courtship, territorial disputes, and hierarchical negotiations. Call structure (duration, frequency modulation, syllable pattern) conveys identity, emotional state, and motivational intent.
- Predator avoidance – mice emit brief, broadband ultrasonic bursts when detecting aerial or terrestrial threats. The rapid onset and high pitch reduce detection by many predators that lack ultrasonic hearing.
- Navigation and echolocation‑like behavior – during exploratory bouts, mice produce self‑generated clicks that provide echoic feedback about nearby obstacles. This acoustic feedback complements whisker‑mediated tactile sensing, especially in low‑light conditions.
- Maternal care – dams respond to pup ultrasonic distress calls with retrieval behavior. The auditory cortex of the mother shows heightened sensitivity to the specific frequency range of these calls, facilitating rapid localization.
Neurophysiological processing relies on specialized cochlear hair cells tuned to ultrasonic frequencies. The basal turn of the mouse cochlea contains outer hair cells with motor proteins that amplify high‑frequency vibrations. Auditory pathways project to the inferior colliculus and auditory cortex, where temporal patterns are decoded. Studies using in‑vivo electrophysiology demonstrate that neurons in the primary auditory cortex exhibit precise phase locking to syllable onsets, enabling discrimination of call variants.
Experimental evidence:
- Playback experiments reveal that adult males increase courtship displays when presented with female‑derived ultrasonic sequences.
- Lesion of the ventral cochlear nucleus abolishes pup‑retrieval behavior, confirming reliance on ultrasonic perception.
- High‑speed videography combined with ultrasonic microphones shows that mice synchronize tail‑flick movements with call emission, suggesting multimodal coordination.
The combination of vocal production mechanisms, frequency‑specific auditory circuitry, and context‑dependent behavioral responses illustrates a sophisticated ultrasonic communication system that supports survival, reproduction, and environmental interaction in the species.