Seismic information transfer in African Elephants - CASE Project

Seismic information transfer in African Elephants
Information encoded in seismic vibrations: How do African elephants perceive seismic vibrations? How do they use them as an information source and for information transfer? Can this be used for elephant conservation? Are other animals participating in biotremology networks?
Growing human populations, particularly in developing countries, are increasingly causing human-wildlife conflict. Elephants in particular, are often associated with human-wildlife conflict due to crop raiding and are additionally faced with severe poaching threats.

Combining biotremology-based experiments and GPS tracking offers a particularly promising interdisciplinary approach to discover novel ways to reduce human-elephant conflict while at the same time increasing our understanding of elephant behaviour and ecology as well as other seismic interactions in the savannah ecosystem.
Detecting and using vibrations that travel through substrates is a largely ignored sensory mode in typical studies of behaviour and ecology (Cocroft et al., 2014). Yet it emerges that such vibrations are used by a wide range of animals (Hill & Wessel, 2016; Mortimer 2017), the study of which is known as biotremology. These include African elephants with O'Connell-Rodwell (2007) demonstrating that elephants can transfer apparently detailed information via infrasonic vibrations through the ground. Specifically, elephants can distinguish between the seismic components of alarm calls generated by familiar and unfamiliar individuals. In theory, these substrate-borne vibrations attenuate less rapidly than comparable air-borne vibrations, and models suggest that elephants can use seismic vibrations to communicate over distances of several kilometres (Mortimer et al., 2018). Importantly for an understanding of biotremology in savannah ecosystems; elephants are apparently not the only large mammals that generate substantial seismic signals for which seismic communication has been hypothesised (O'Connell-Rodwell et al., 2001). Specifically, O'Connell-Rodwell et al. (2001) suggest that black rhino may use seismic signals to form loose groups that coordinate a synchronised arrival at watering holes at night. Advances in technology have made the study of seismic communication more tractable and we propose to use this modus operandi to update our image, using elephants as a focal animal of the savannah ecosystem and its mammals. For this we will use a combination GPS tracking, biotremology techniques, and in-situ observation and experiments.

GPS tracking technology provides unique insight into the spatial distribution of elephants and can consequently remotely indicate interactions between individuals. Observations of tracked male elephants moving in parallel over several hours but kilometres apart suggest that they communicate probably via the ground (Douglas-Hamilton and Vollrath unpublished observations). However, the ability of GPS data to conclusively demonstrate interactions will rely on novel biotremology technology to demonstrate cause and effect based on a combination of experiments and observation (Mortimer et al., 2018).