What is the main idea of the passage?

Elephants use low-frequency rumbles for social contact across distance, within a sound world partly beyond human hearing. (The passage explains infrasonic components, social use, environmental effects, and more than one signal path.)

Why might a person hear only part of a rumble?

The call can contain both audible components and frequencies below ordinary human hearing. (The first paragraph distinguishes the full signal from the portions humans can hear or feel.)

What does “infrasonic” mean here?

having a frequency below the usual range of human hearing (The first paragraph directly defines the word through the human hearing limit.)

Which body parts may receive ground vibration?

the feet and trunk (The third paragraph names feet and trunks as possible receivers of vibration.)

Elephants Talk Below Our Hearing: Level 2 Reading Comprehension Questions

Elephants produce many sounds, including low rumbles. Some parts of these calls fall below the usual lower limit of human hearing and are called infrasonic. People may feel vibration or hear higher parts without detecting the whole call.

Low-frequency sound can travel over long distances under favorable conditions. Elephants use rumbles in social communication, helping separated animals maintain contact. The signal may carry information about the caller and situation, while listeners respond according to context.

Distance is not fixed. Wind, temperature layers, ground, vegetation, and background noise affect how far a call remains useful. Elephants also receive vibration through their feet and trunks, though researchers continue to study how airborne and ground-borne information work together.

Calling below our hearing does not make the exchange silent. It reveals that an animal's sound world can extend beyond the frequencies human ears notice.

Comprehension questions