Can a Platypus Sense Electricity?
The German word umwelt refers to the unique sensory experience of an animal. One of my main interests is research about senses that humans do not have. A personal favorite is electroreception, which refers to the ability of some animals to sense (and sometimes produce!) electric fields. Fish and amphibians are usually in the spotlight in electroreception studies; however, the platypus is one of the only non-amphibian tetrapods that has not lost this ability1. Specialized organs on their bills help them detect these electric fields.
When a platypus is underwater, it swims with its eyes, ears, and nares (platypus nostril equivalent) closed, but it can still find its prey. Researchers in the 80s did some experiments to test whether these platypuses were finding their prey by sensing electric fields.
They placed a platypus in a pool with a battery at some random location. The platypus was able to locate it and "attack" it with 100% success rate! This ability is likely used to detect the electricity generated by muscle movements of their prey.
In another experiment, a shrimp tail, an active battery, and a dead battery were all placed in the pool at the same time, and the platypus showed a clear preference for the active battery2. This coincides with the finding that platypuses feed exclusively on live prey.
Electroreception is completely foreign to the human sensory experience. Like Thomas Nagel says, conscious experience occurs "in countless forms totally unimaginable to us"3. I am excited to see what else scientists will find about how other animals sense the world around them!
Electroreception is an ancient trait, and it is believed that the first vertebrates already had the ability. Many aquatic species retain electroreception, while most land-dwelling animals have lost it over evolution.↩
Scheich, H., Langner, G., Tidemann, C., Coles, R. B., & Guppy, A. (1986). Electroreception and electrolocation in platypus. Nature, 319(6052), 401–402.↩
Nagel, T. (1974). What Is It Like to Be a Bat? The Philosophical Review, 83(4), 435–450.↩