Humans have five traditional senses: taste, touch, hearing, smell, and sight. Some animals have additional ways of perceiving the environment beyond human capabilities. While this list is not all inclusive by any means, it is a small sample of some astonishing ways to experience the world.
Image credit: Tambako the Jaguar
Echolocation works by calling out to the environment and interpreting the echo response. The time it takes the echo to bounce back lets the animal judge distance of other objects and animals.
Many animals use this technique to navigate and find food, and some, like dolphins and bats, are not closely related. It was revealed last month that echolocation is the product of convergent evolution. Instead of the trait being passed down from a common ancestor, the same genes mutated independently, resulting in the ability to echolocate.
It has been known for a while that blind humans can echolocate to navigate in the environment, but it is a skill that sighted people can learn as well, according to new research. It is likely that humans typically tune out most echoes in order to hear human speech more clearly, but with training and learning how to focus, it is possible to be good at both.
Image credit: Terry Goss
The ability to sense electrical fields in the water is nearly exclusive to fish and amphibious animals because electricity is conducted better in water than in air. The ability to sense the electrical impulses from other animals is also beneficial in areas when sight is restricted, such as at night or in poor water quality.
Electroreception works somewhat like a battery. When another animal contracts its muscles to move electrical impulses are generated. Those impulses travel out into the water where they will exchange electrons with sodium and chlorine ions. This interaction stabilizes the charge and makes it easier to be read by another animal.
While it is well known that sharks and several bony fish are capable of electroreception, it might be less known that dolphins, duck-billed platypuses, and even bees utilize it to find food. In the case of bees, a small electric field is left on a flower after it has been pollinated. This allows other bees to see which flowers are still available, and which would be a waste of time to visit.
Image credit: Regani
After noticing that the beetles they were studying mated less when rain was in the forecast, a team of researchers decided to study three unrelated species of insects to test their hypothesis that the insects were predicting the weather. Controlling for light, humidity, and temperature, the team varied the pressure and noticed that insects were less interested in copulation as the pressure dropped, as it does when rain is imminent. Researchers believe insects behave this way to protect themselves from potentially life threatening rainfall, preferring to take cover instead of copulate.
Cobitidae is a family of fish commonly known as weather loaches. These fish respond to the change in pressure by swimming erratically, as if they are looking for a way to escape the environment.
Image credit: Brocken Inaglory
One of the most amazing animal senses is the ability for many animals to tap into Earth’s magnetic field for navigation purposes. It was proposed recently that this ability comes from iron-rich crystals in cells that move in response to the magnetism. In essence, these crystals might act like built-in compasses by adding pressure on these cells, pointing the animal in the right direction.
Many of the animals with the ability to get directions from the Earth are migratory, such as sea turtles. However, invertebrates like fruit flies, nudibranchs, and even certain bacteria are affected by magnetic pull.