Perception
The famous philosopher Aristotle was the first to assign humans with five traditional senses: sight, hearing, touch, taste and smell. However, if he was categorizing animals, his list of senses might have been longer. Several animals possess additional perceptive abilities that allow them to experience the world in ways we can barely imagine
Pit vipers
Venomous snakes of this family of are most easily identified by a pair of deep "pits" that can be found between the nostril and the eye. These pits are actually heat-sensing organs that allow the snakes to see in infrared — an invaluable sixth sense for a predator that often hunts at night.
The sense is so sensitive that pit vipers can accurately judge the distance and size of their prey even when their other senses are deprived.
These charismatic sea mammals have the incredible sixth sense of echolocation. Because sound travels better in water than in air, dolphins are able to create a three-dimensional visual representation of their surroundings based entirely on sound waves, much like a sonar device.
This is a necessary adaptation, especially for river dolphins, because vision is often extremely limited in murky water. Dolphins can navigate through a river of tangled branches with ease even if their eyes completely covered.
Sharks
Electroreception is the amazing ability of sharks and rays to detect electrical fields in their surroundings.
In fact, the strange shape of a hammerhead shark's head is specially designed for an enhanced electroreceptive sense. Because salt water is such a good conductor of electricity, sharks with a refined sixth sense can detect their prey from the electrical charges that are emitted when a fish contracts its muscles.
The sense is so sensitive that some sharks can pick up the change in electrical current of two AA batteries that were connected 1,000 miles apart, even if one was drained out.
Bats
Many insectivorous bats, often referred to as "microbats", are capable of using echolocation to catch their prey and for navigating through dark caves and the night sky.
They have a larynx capable of generating ultrasound, which they emit through their mouths or nose. As the sound echoes through their surroundings, sound waves bounce back and give the bats a radar-like "view" of their surroundings. In fact, these bats often have strange, wrinkled faces that function like an ear to better pick up the sound.
Platypus
These bizarre, duck-billed, egg-laying mammals have an incredible sense of electroreception that is similar to the sixth sense of sharks. They use electroreceptors within the skin of their bills to detect the electrical field that gets generated when their prey contracts its muscles.
A platypus swings its head from side to side while swimming as a way to enhance this sense. The bill is also lined with mechanoreceptors, which give the animal an acute sense of touch and make the platypus' bill its primary sense organ.
Butterfly
Butterflies don’t really have mouths, much less taste buds, to help them decide if food tastes good or bad. Instead, they use their feet!
To eat, a butterfly unwinds a long, skinny part of its body called a proboscis, and sucks up liquids like nectars and juices. It works for nutrients, but the proboscis does not have sensors to determine taste. Instead, those sensors are located on the back of the butterfly’s legs. The insect will step on its food to sense dissolving sugars. Even more importantly, a female butterfly will use her feet to drum on a plant and “taste” its juices. This helps her decide if the leaf would be edible to a caterpillar, and therefore, if she has found a suitable place to lay eggs.
