Animal Senses That Humans Don’t Have

Author: Lillian Dong

Editors: Joshua Payne, Oscar Chen

Artist: Christina Chen

A human’s world is composed of five senses: sight, smell, hearing, taste, and touch. Many people believe that these senses encompass everything there is to be experienced, but have you ever thought of “seeing” which direction points north? Or “feeling” the electrical field around a friend? Trying to imagine senses that humans do not possess is like trying to see out of your elbow, so in this article, let me introduce the world of the unique senses that you will never naturally experience.

To begin, animals utilize advanced versions of the senses that humans are familiar with. Many are already aware of the heightened senses of animals like dogs, but did you know that some insects taste with their feet? Entomology experts explain that flies, ants, and many other insects have hair-like taste sensilla on their feet, which are equivalent to our own taste buds. Additionally, some insects can even taste fatty acids, metals, RNA, and pheromones. This heightened sense of taste helps insects detect toxic or aversive compounds before they enter their mouths. Similarly, catfish have taste organs all over their bodies, and they can taste the proteins of the surrounding water to detect food. Although many people associate taste with the pleasure of eating, certain animals need it to hunt and forage for food.

Aside from taste, the ability to see color is also a key differentiation. Humans have three cone cells in their eyes that blend into the full spectrum of the rainbow. However, most birds, along with some reptiles and fish, have four cone cells. This allows them to see ultraviolet light, which is invisible to the human eye. Through advancing technology, scientists have created models that show how these animals perceive the world, and as it turns out, their natural vision is much more vibrant than ours. In the same way, dogs are colorblind when compared to humans; humans are colorblind when compared to birds.

Many animals can also sense things that humans have no experience with. One example is magnetoreception, the ability to sense the Earth’s magnetic field. It took humans decades to develop the compass, but birds are born with it. Although the specifics are still unknown, a leading theory suggests that this skill originates from cryptochromes in a bird’s eye. Cryptochromes are proteins located on the outer surface of cone cells that respond to light. Once light is absorbed, a series of chemical reactions occurs to form a radical pair–a pair of molecules that each have an unpaired electron. Then, the two unpaired electrons will either both spin in the same direction or opposite directions. In birds, researchers have concluded that magnetic waves can control the spin of these electrons, and this alteration is translated into the brain as a signal that indicates if the bird is facing north or not. Magnetoreception plays a crucial role in migration and navigation in birds.

Another example of a more unique sense is electroreception. All plants and animals generate a small electrical field due to the movement of charged particles throughout all cells, and sharks are among the many animals to take advantage of this. Sharks utilize a special organ called the ampullae of Lorenzini that appears as jelly-filled pores all over its head. The jelly is composed of keratan sulfate, the most conductive biological compound, and within these pores are numerous nerve fibers. This creates a system so sensitive that scientists believe some sharks could detect a difference in electricity when two AA batteries were connected 10,000 miles away. In the wild, their keen senses enable sharks to detect electrical stimuli from their prey’s muscular contractions, significantly enhancing their ability to locate food. Electroreception may seem foreign to us, but in murky and dark waters, it may be the only way for an organism to see.

These senses unique to certain animals are only the beginning of an entire world beyond what humans naturally experience. Nonetheless, what surpasses any sense is the unbounded human intelligence. While not born with these senses, humans have developed tools to enhance their experiences, including compasses and specialized cameras. We may only have five senses, but that doesn’t mean we are experiencing the world any less.

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Citations:

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Leffer, L. (2024, January 23). Animals Can See Colors We Can’t—And New Tech Offers Us a

Glimpse. Scientific American. https://www.scientificamerican.com/article/animals-can-see-

colors-we-cant-and-new-tech-offers-us-a-glimpse/

The Sixth Sense of Sharks. Catalina Island Marine Institute. (2021, June 18). https://cimi.org/blog/the-

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Wiltschko, R., Nießner, C., & Wiltschko, W. (2021). The Magnetic Compass of Birds: The Role of

Cryptochrome. Frontiers in Physiology, 12. https://doi.org/10.3389/fphys.2021.667000