Having an accurate perception of the environment is vital in the day to day of any animal and fundamental to its survival. Usually, they can perceive and interpret their surroundings quite easily, through basic senses, like sight, hearing or smell.
However, some animal groups have developed a series of complex sensory organs and systems, adapted to their ways of life, that allow them to receive and accurately interpret a huge amount of data. In this article, you’ll learn about some of these amazing systems and mechanisms. But first…
What is perception?
The Cambridge Dictionary defines perception as “the awareness of things through the physical senses”, an awareness that will depend on the information collected by the sensory organs and the brain’s interpretation of it. Perception is an interpretation dependent on context and requires a chemical or mechanical stimulation of the special nerve cells (the receptors).
In some cases, certain features that manifest in the external environment can only be recognized through detailed organisation and a complex reading of the messages that reach the brain. In this sense, the most arduous interpretations of the different stimuli usually require individuals to develop high cognitive capabilities that will enable them to effectively examine and control their environment.
However, a high degree of adaptation doesn’t always require a great sensory equipment or accurate representations of the environment. Animals have adapted (and refined) a series of sensory systems and organs in order to receive the information as quickly and effectively as possible. In the following paragraphs, you’ll discover three of the unique information systems and sources used by different animal groups and species.
The lateral line system
The lateral line is a sensory organ present in a wide variety of aquatic vertebrates. It’s a structure that consists of a series of longitudinal channels that run lenghtwise down each side of the animal’s body, tracing a line that’s usually visible to the naked eye. This system is also composed of a series of receiving cells called ‘neuromasts’, which are in turn formed by a group of hair cells, in charge of collecting information and perceiving the movements of water.
Animals that have this unique organ can easily detect the movements, vibrations and changes that occur as water flows, which helps them to avoid potential collisions and guides them when swimming. The lateral line also allows them to identify predators, prey or objects in a very precise way. A rather amazing example of the efficiency of the lateral line is the case of some blind fish that live in caves with little to no light, which can perceive objects smaller than the head of a pin. In any case, it’s important to note that the most detailed and accurate images are usually obtained when fish move at high speeds.
Although, in general terms, this organ behaves and works similarly in all organisms in which it’s present, some animals have developed a unique lateral line, such as cephalopods and some amphibian larvae.
The detection of electric fields
Electrolocation is the ability that some animal species have to detect electric fields in their environment, which they use to locate other organisms, communicate, locate objects and orient themselves. This mechanism is only viable in aquatic environments (and especially in marine environments), as the physical-chemical properties of water make it an excellent electrical conductor (unlike air, which acts as an insulator in this case).
But what are these mechanisms and how does electrolocation work? These fish have a series of ‘electric generators’ in their body. The generators produce a series of electric discharges (from 1 to 10 volts) that expand in circles with the movement of the fish and that each individual will be able to perceive, thanks to the presence of thousands of sensors.
Depending on how the electric current flows through the elements of the environment, the animals will see one image or another; rocks are dark (they have insulating properties), while plants and metallic objects are perceived as bright, as they are better conductors. This differentiation between conductive and non-conductive objects allows animals to perceive distances and shapes.
They perceive the images in flashes, which will become more recurrent and faster as the speed of the electric pulses increases. In this sense, while some species are able to generate hundreds of discharges a second, obtaining an almost continuous image, others will perceive the world in less detail, as they produce discontinuous discharges every few seconds.
The interpretation of echoes
Echolocation, also called bio sonar, is the ability that some animals have to perceive their environment through the emission of specific sounds and the subsequent interpretation of their echoes. This is how it works: when the sound waves emitted run into any object, element or animal in their path, they bounce off and echo back to the transmitter with a lot of valuable information.
Animals that use echolocation in their daily lives, such as bats or dolphins, usually emit high-frequency sounds; as such sounds are very rare in nature, it’s unlikely for them to pick up interferences during the reception of echoes, and therefore interpret their environment in a more precise way.
Echolocation is a system used by some species to obtain information about the elements in their environment: their size, weight, speed, direction… This is one of the most important and unique perception mechanisms in the animal kingdom.