Why do rats coo like pigeons? - briefly
Rats emit soft, low‑frequency coos when they are relaxed or interacting with other rats, a vocal pattern that mirrors pigeon cooing because both species employ comparable harmonic structures to signal calm and social affiliation. This resemblance results from convergent evolution of acoustic cues that convey non‑threatening, affiliative states.
Why do rats coo like pigeons? - in detail
Rats emit low‑frequency vocalizations that sound remarkably similar to the soft coos of pigeons. The similarity arises from several physiological and behavioural factors.
The rat’s larynx can produce a range of frequencies, including a broadband “soft squeak” around 400–800 Hz. This sound is generated by rapid vibration of the vocal folds while the animal is calm or engaged in gentle social contact. Pigeons, when cooing, also use low‑frequency tones produced by airflow through the syrinx, the avian equivalent of a larynx. Both species therefore rely on relatively low‑pitch sounds for close‑range communication, creating an acoustic overlap.
Key reasons for the convergence include:
- Social bonding: Both animals use the gentle call to reinforce pair bonds or maintain group cohesion. The sound’s modest intensity reduces the risk of attracting predators while still being audible to nearby conspecifics.
- Anatomical constraints: The size and shape of the rat’s vocal tract and the pigeon’s syrinx limit the resonant frequencies to a similar band, making low‑frequency output the most efficient.
- Environmental adaptation: In dense habitats—underground tunnels for rats, urban structures for pigeons—low‑frequency sounds travel with less attenuation, enhancing communication effectiveness.
- Neural control: Brain regions governing vocal production in mammals and birds share comparable patterns of rhythmic activation, leading to analogous sound modulation when the animals are in a relaxed state.
Research on rodent ultrasonic communication shows that rats switch to higher‑frequency calls under stress, while the soft coo persists during non‑aggressive interactions. Parallel studies on pigeons demonstrate that the coo is suppressed during flight or alarm situations, reinforcing its role as a calm‑state signal.
In summary, the coo‑like call of rats results from convergent evolution of low‑frequency vocal mechanisms that serve social bonding, predator avoidance, and efficient sound transmission in confined environments.