Reaching out horizontally with a full extension of the trunk to inspect a nearby object or scent that the elephant apparently does not wish to approach closer. The elephant typically stretches its body in the direction of interest and then elongates its trunk several times to its fullest extension. The manoeuvre appears to take some effort on the part of the elephant, as it does not seem to be able to maintain this full extension for more than a few seconds.
References: Kahl & Armstrong 2000; Poole & Granli 2003; Poole & Granli 2011 [Trunk-Extension-Sniff]. (Full reference list)
This behavior occurs in the following context(s): Attentive