Boogie wonderland: new research shows elephant fish dance to see in 3D
15 September 2023
Body movements are utilised by many species to help improve perception of their environment which is needed for successfully navigating through space, sensing prey, and avoiding predators.
New research from Sarah Skeels and Theresa Burt de Perera at the Department of Biology has investigated a specific type of electro-sensitive fish, and how they use interesting movements for sensing, that could be interpreted as dancing.
The team used elephantnose fish, native to western and central Africa, and named after their trunk-like appendages which contain electroreceptors. They found the fish use movements such as twisting, pacing, and shimmying to “see” objects by interpreting the changes to the electric field around them. The fish themselves produce a small electric discharge from an electric organ in their tail. Objects within the self-generated electric field will distort it, and these changes are detected by specialised receptors on the skin. This unique ability is known as active electrolocation and is found in only two lineages of freshwater fish.
The researchers trained six fish to distinguish between two aluminium blocks of different shapes – sausage-shaped vs. cubed or spherical – set side-by-side behind mesh partitions in a tank. The fish were given food as a reward when they opened a door in the partition that led to the correct-shaped object with their “Schnauzenorgan”, the trunk-like chin appendage that gives them their elephantine look.
With sufficient space in the tank, the fish were correct 94% of the time. However, when space was reduced, meaning that scanning movements around the objects were limited, their accuracy dropped significantly.
The researchers think the fish are using their electric pulses to create a series of snapshots as they move near an object’s surface. This sequence of scans, working like a flipbook animation felt by the skin through varying movements, can reveal the object’s shape.
This fits with the “multiple looks hypothesis”, which is thought to play a role in other animal senses, such as vision, with the idea being that by looking at something multiple times and from different perspectives, you can get more information about that thing.
Dr Sarah Skeels, lead author on the paper, said:
“Our work shows that movements play an important role in perception in these fish, providing them with information that would otherwise be seemingly inaccessible. More broadly, the principles uncovered in this study can be applied to understanding the sensing strategies of other animals using a variety of senses.”
In the video below, an elephantnose fish, “Peanut”, chooses the correct shaped object and receives a food reward (bloodworm) as a result. They then return on their own accord, ready to start the next trial.
