Is it true that rats are capable of laughing? - briefly
Rats produce high‑frequency ultrasonic chirps during play and tickling, which researchers interpret as a laughter‑like response. These vocalizations suggest that rodents can experience a positive emotional state akin to mirth.
Is it true that rats are capable of laughing? - in detail
Rats emit ultrasonic vocalizations that resemble a form of laughter when they experience pleasant physical stimulation, such as gentle tickling. These sounds occur at frequencies above 20 kHz, beyond human hearing, and are accompanied by characteristic body movements, including rapid, high‑frequency chirps and a relaxed posture.
Experimental observations show that when rats are tickled, they produce “50‑kHz” calls, a frequency band associated with positive affect in rodents. The calls increase in number and intensity with repeated sessions, indicating a learned association between the stimulus and a rewarding state. Conversely, distress or pain triggers low‑frequency “22‑kHz” calls, which serve as alarm signals.
Neurophysiological studies link the emission of these high‑frequency vocalizations to activation of the nucleus accumbens, ventral tegmental area, and dopaminergic pathways, mirroring the reward circuitry engaged during human laughter. Pharmacological blockade of dopamine receptors reduces the frequency of the calls, further supporting the connection to pleasure mechanisms.
Key findings from peer‑reviewed research:
- Behavioral context – Tickling, social play, and anticipation of food reward elicit the high‑frequency calls.
- Acoustic properties – Calls consist of short bursts (10–100 ms) with a peak around 50 kHz; they are not audible to humans without specialized equipment.
- Physiological correlates – Increased heart rate variability and dopamine release accompany the vocalizations.
- Comparative relevance – Similarities in brain activation patterns suggest an evolutionary precursor to human laughter, though the expression differs in modality and perceptibility.
In summary, rats possess a laughter‑like response that manifests as ultrasonic chirps during enjoyable interactions. The phenomenon is well documented, grounded in measurable neural activity, and distinct from vocalizations associated with fear or pain.