V8-Rumble
A short (1.1-1.8 seconds) groaning-sounding Rumble given by an adult male who is on the receiving end of a serious threat. The call has the quality of an outboard or V8 engine, thus its name. The V-8 Rumble is similar in acoustic structure and in social context to a Grumbling-Rumble and it is possible that its deeper, more resonant quality is merely because it is produced by much larger individuals. Adult males may produce this call in several specific circumstances including: When seriously threatened at close range by a higher-ranking (often musth) individual; when chased or lunged at by a higher ranking individual; during rough sparring matches or other rough play.
This call appears to be produced only by males and seems to indicate submission; the attacker usually stops when his or her opponent has vocalized.
References: Poole 2011. (Full reference list)
This behavior occurs in the following context(s): Submissive, Protest & Distress