A soft, flat, tonal rumble of medium duration (~2.5-4.5 seconds) and low pitch, given by adult or juvenile females in the context of caring for an infant or young calf. There are two broad behavioral contexts in which females call in this manner to a calf with whom they are in close proximity. One is when they greet, touch, suckle or generally "coo over" a calf in the absence of an expression of distress by the calf. Such calling is directed toward infants, rather than older calves, and is especially frequent when there is a newborn in the family. Juvenile females may also call in this manner when touching infants and when they encourage infants to Comfort-Suckle from them. Such touching induces calves to respond with a rumble (see As-Touched-Rumble).
The other context is when adult or juvenile females reassure a calf following an event that has caused the calf to give some form of distress call. Husky-Cries, Begging-Rumbles, Separated-Rumbles, Baroo-Rumbles, Alarm-Trumpets, Cries and Roars all elicit this type of calling by family members. We refer to these calls collectively as Coo-Rumbles.
References: Poole 2011. (Full reference list)
This behavior occurs in the following context(s): Birth, Calf Nourishment & Weaning, Calf Reassurance & Protection