A short (<1 second) tonal vocalization that is almost always followed by a rumble without an exhalation. Revs have a harmonic structure and appearance similar to a short rumble, but its fundamental frequency (50-90 hz) is significantly higher and have a buzzing or revving quality as if vibrating in the nasal cavity much like a nasal trumpet. Revs are very rarely heard in the wild and little is known about their usage, although they seem to be associated with high arousal, such as during greetings.
Another adult female in the group walks toward Lorato and Mama Little E and Mama Little E displays Head-Raising and Ear-Lifting in a typical Little-Greeting posture. We can hear a Rev-like sound by her and then, another immediately after by the female in the foreground who approached her and also Head-Raises and Ear-Lifts. Normally this would be associated with rumbling, but we see no evidence of this. They stand side-by-side, but it is also clear that this is a Supplant.
The older female came very purposefully and displaced Mama Little E from where she was feeding. As this goes on Lorato looks after Little E. Note that we have called this a Rev since the sounds came from the elephants' mouths not from their trunks. (Maasai Mara, Kenya)