Some aspects related to certain capacities of animals have been the subject of controversies and debates in the scientific world. An example of this is the topics related to intelligence, memory and sensations such as pain, which have increased in number of studies. Efforts have focused on discovering whether or not these characteristics are present in animals, as well as how.
In this article on our site we are going to review the information available regarding the memory of fish. Read on to find out if fish have memory and what their characteristics are.
The memory of the fishes
Fish are vertebrate animals, which means that there are certain traits that they share with all the species that make up this group. Thus, these aquatic animals have certain basic characteristics of the most evolved vertebrates. With regard to memory and learning, the scientific literature [1] affirms that, without a doubt, both are aspects present in fish and in a comparable way to other more evolved vertebrates.
In addition to the various studies that have been carried out proving this statement, a practical way to observe that fish have memory is to familiarize them with feeding routines, that is, offering them food in the same place and at the same time.
We will check that the fish respond by coming at that exact moment to eat, which leads us to think that it is a consequence of their memory capacity. On the other hand, it has been verified in certain species of fish that, if they are caught by a hook from which they manage to free themselves, they are capable of recognizing this trap later, thus avoiding falling into it again.
Fish have a complex sensory system, as shown by sharks, undoubtedly linked to the type of habitat in which they live, since anatomical and physiological strategies are required to develop properly. The examples of memory mentioned allow us to specify that memory is linked to sensory abilities In other words, fish collect information from the environment and use it to create mental maps that allow them to orient themselves spatially, move, locate escape routes from predators or reproduce.
This memory capacity has been attributed to the cerebrum, a brain structure with different levels of development depending on the group of vertebrates. In this sense, the research carried out on the memory of fish has made it possible to establish which biochemical, morphological and ecological aspects are linked to this capacity and to the telencephalon.
Why is it said that fish have no memory?
There was a widespread and erroneous idea that fish had no memory, probably because these animals belong to the most primitive vertebrates in the evolutionary scale. For this reason they had been attributed some limited brain capacities, which included memory.
But this belief, as has been shown, is still a myth, which has propagated itself in the collective imagination, as evidenced by the jokes regarding its inexistence of memory. Today, as we have explained, this myth can be refuted thanks to the evidence provided by scientific research.
As a curiosity, it can be stated that these animals even have a more complex sensory system than that of humans. There are not a few species of fish capable of perceiving olfactory, visual, auditory stimuli, particles dissolved in the water, such as blood in the case of sharks, and electromagnetic frequencies. All these aspects make possible another feature present in them, which is the individuality of response to certain situations, for example, stress.
How long does a fish's memory last?
The memory of the fish can have different lengths, depending on the event with which it is related. In this sense, there are references [1] that indicate that fish avoid approaching a hook for months if they have had a previous negative experience with it. This approach leads us to another important aspect, which is that memory in fish is also linked to the learning of certain behaviors, in this case avoiding being the victim of a hook.
On the other hand, some species manage to recognize members of their group for up to seven consecutive days and in the case of individuals of other species with whom they have had a confrontation it is stated that they remember them for up to three months.
It has also been shown that fish are able to remember negative stimuli experienced in a certain area, so they avoid approaching it. Additionally, in some species it has been observed that if a fish sees two others facing each other, it will avoid approaching the winner. All these aspects are undoubtedly linked to the short-term and long-term memory present in these chordates.
By way of conclusion, these types of studies, like those related to the ability to feel pain, are important to promote the respect that must be shown to all animals, not so much because of their similarity to humans in some traits, but rather by the intrinsic characteristics of their species that define them as living beings.
