#14: Elephants – Infrasound
Elephants can communicate with calls so low that part of the signal falls beneath the lower frequency limit of normal human hearing. These infrasonic vocalizations can travel considerable distances, particularly under favorable atmospheric conditions, allowing separated animals to remain acoustically connected across large landscapes. Elephant calls often contain both audible and infrasonic components, so a person standing nearby may hear a rumble without perceiving its deepest frequencies. Researchers have documented elephants responding to distant calls from family members and other individuals, demonstrating the importance of low-frequency communication within their complex social lives. Information carried by rumbles can relate to identity, reproductive state, alarm, coordination, and social contact. Elephants are also highly sensitive to vibrations transmitted through the ground, and evidence indicates that seismic signals produced by vocalizations or movement can be detected through their feet and bodies. That creates a communication environment involving both air and earth. Exactly how far any particular signal travels depends on terrain, weather, frequency, and background noise rather than one fixed maximum distance.
