Assertion: okapi's mother | /r/CapableOf | communicate with their calves
Facets:
value: by releasing infrasounds
type: MANNER
Source sentences:
text: Mothers will also communicate with their calves by releasing infrasounds—
text: Moreover, they can communicate with each other using infrasonic sound which cannot be heard by human beings and this is quite useful for mothers to communicate with their calves without being detected.