Research project: Elephant trunk

One of the most conspicuous features of elephants is their trunk. It plays an important role in food uptake, drinking and social behavior. The trunk is also employed in tool use and elephants can apparently even be differentiated into those that prefer left-“trunking” or right-“trunking”.

Aim

This research project focuses on the tactile behavior of African elephants and particularly on the many types of behavior involving touching with the trunk. In order to close the gaps in our knowledge of how the trunk is used, the elephants at Schönbrunn Zoo are being examined in detail.

Relevance

Currently no comprehensive data are available on how exactly and how often African elephants use their trunks in comparison to other body parts. A better understanding of this aspect would help to tailor future experiments testing the cognitive abilities of elephants to their specific capabilities.

Method

The tactile behavior of African elephants at Schönbrunn Zoo was documented based on an observation protocol, supported by photo- and video material. For this purpose, each elephant cow was observed separately over the course of several hours. This was supplemented by feeding experiments along with photographs and video recordings to document how elephants employ their trunks. The insights resulting from these observations were then combined with detailed neurobiological analyses of elephant brains and facial nerves.

Results

The results of this study showed, that African elephants have approximately 63.000 neurons in their facial nucleus – a nerve complex in the brainstem, which is responsible for coordinating facial and ear muscles. This number is uniquely high amoung all terrestrial mammals including humans. Their trunk alone consists of more than 30.000 muscles and is able to make sweeping and far-reaching movements, but can also pick-up minute objects or get a sensitive feel for a surface using their so-called trunk fingers. The research team around Lena Kaufmann also found out, that Asian elephants, with only one trunk finger and smaller ears have a less complex facial nucleus with „only“ around 54.000 neurons.

Literature

Kaufmann, L. V., Schneeweiß, U., Maier, E., Hildebrandt, T., & Brecht, M. (2022). Elephant facial motor control. Science Advances, 8(43), eabq2789. https://doi.org/10.1126/sciadv.abq2789