This exercise is a personal and empirical reflection that I hope will raise both scientific and philosophical debates, built on the acquisition of intelligence, cognition and memory of sharks in the presence of man.
Nothing in the history of evolution has prepared these two species for this ultimate encounter. How will these two predators react in environments so different from each other? What will be the tools used to better decrypt the other? How to understand one another? Which communication to adopt? The foundation of these thoughts is based on examples of scientific experiments, historical facts and the accumulation of thousands of shark diving.
The word "cognition" comes from Latin cognitio, action of knowing. Cognition is the set of mental processes that relate to the function of knowledge and involve memory, language, reasoning, learning, intelligence, problem solving, decision making, perception or attention. The word "intelligence" comes from the Latin word intellegentia, faculty to perceive, to understand. The verb intelligo, intellegere refers to understanding, grasping through thought, realizing, etc. Intelligence can be defined by all the processes found in systems, more or less complex, alive or not, that allow to understand, learn or adapt to new situations. Intelligence is often equated with the ability to process information to solve new problems. The term "memory" refers to different things depending on gender, domain and context. The origin of the word memory is formed from the common name of Latin origin the memory which means memory. Memory is the ability to preserve and restore past things. In the context of animal memory we will speak here of genetic memory, long-term memory, short-term memory and sensory memory.
The debate on shark intelligence, cognition and memory is extremely sensitive, controversial and confronts two worlds:
- The scientific world, which bears witness to knowledge and studies of universal value, acquired and characterized by a methodology and based on verifiable objective observations and rigorous reasoning;
- the empirical world which is based exclusively on experience, observation and interpretation, without following scientific methods and principles.
These two universes fight over a truth that goes beyond knowledge. Semantics raises the supreme question of the distribution of intelligence among animals on Earth as well as the place of man in the Universe. Do we have the cognitive tools and the intelligence to understand the infinity of the Universe? Perhaps we are not "equipped" to understand the immensity of the Universe and the notion of infinity? What is often used as an analogy to explain this lack of equipment is the comparison with the dog: "Do you think your dog is intelligent?" - Yes - do you think he understands you? Yes - Then try to explain to him, since he is intelligent, the theorem of Pythagoras, or ask him to think about the inconsistency of the human race… ”
This is where the perspective comes in between cognitive equipment that allows the dog to associate events but does not give him the ability to create analytic added value and even less to have a conscience. Dogs and humans can nevertheless be considered "intelligent", each in a field that allows them to understand their environment ... Man, by extension, would not be made to understand the universe. It is not his environment, and it would be, at this stage of evolution, illusory to believe that he has a place and a role to play in a space that is not made for him.
By this demonstration, we are not claiming that sharks are not intelligent. We are simply suggesting that their intelligence is adapted to their environment, lifestyle and adaptability (learning to adapt to environment / prey / predator / defense, etc.). In this general sense, sharks show intelligence, but is this intelligence sufficient to manage the arrival of humans on their territories?
To date, only Dr. Samuel Gruber and a few other scientists have considered the shark's point of view in their cognition analyzes. Most research on the intelligence, cognition and memory of sharks has most often been studied from the point of view of humans and apprehended by the public through the filter of anthropomorphism. Yet this is the first trap to avoid when it comes to studying the behavior of an animal, which is a living fish with a relationship to the environment totally different from ours, terrestrial.
The diagram below shows a reaction tree in the shark in its everyday life (Fig. 3). The table (fig. 1) represents the range of choices that a shark can take depending on the stimuli received by its senses. The more a box is filled with a catalyst, the more it will lead to behavior.
This quest for understanding involves language and communication mode translation. Men do not speak the language of sharks. They will adapt their observations to existing knowledge of other species. This treachery of vocabulary that is not adapted reveals the true gulf that separates us from the truth. That is why, before each analysis, we must remain as modest as possible and realize that we know very little about it. It is advisable to "kill" misconceptions, to avoid personal interpretations and to admit that we do not know.
The cognitive system of elasmobranchs (the taxon of cartilaginous fish) to which sharks belong evolved differently after the separation between the two large groups of fish hundreds of millions of years ago. Bony fish have developed a brain with a memory mechanism. Cartilaginous fish have inherited the perfection of their senses to compensate for the loss of non-development of their brain in terms of memory. They still have a cognitive system but that seems limited compared to that of bone fish in terms of memory.
Because of their age on Earth, the shark brain is called primary. The survival tools that sharks use are based on the ability to analyze the catalysts that feed their seven senses and then trigger stimulus-appropriate behavior. Sharks are driven by a more instinctive behavior than thought, served by very developed senses. A branched tree of actions to be performed will indicate what action needs to be accomplished based on the stimuli encountered in the daily life of sharks. The instincts (variable depending on the species of sharks, their environment, their diet, etc.) will complete the analysis that will activate the attitude to adopt in the situation. This exercise could explain the binary brain (on / off) sharks that from one moment to another completely change their behavior, get excited, then return to rest. This could demonstrate that sharks do not have free will, that they do not choose and do not reason. A reflex reaction to the slightest catalyst makes them react to every opportunity: they collect information and continue to satisfaction, or they give up.
The drawing (fig. 2) is a summary of sharks' senses and their range.
Since man does not exist in the instinctive memory of sharks, they have neither the codes nor the resources to fully assimilate who we are. Therefore, sharks do not have a sense of deduction when it comes to analyzing a human. For a shark, a man represents a living "organism" unrecognized in his daily life that moves differently from other marine animals, has a different smell, different behaviors and a relatively low time in water. To deepen its observation, the shark will rely on the information received at different distances by its short and long range detection devices and be based on an analysis of the actions to be adopted according to the stimuli detected. It will continue to collect the information necessary to place this organism (the human) in one of the boxes: prey, predator, ally, fish useful for its well-being, danger, etc. (See Table 1). The examination can quickly be abandoned if the shark finds no interest in it (linked to the stimuli received), or continue depending on the data collected until contact if necessary. Touch can in some cases make it possible to better assimilate the nature of man. In extreme cases, not having a hand, the sharks to better soak up the texture and reactions, have no other recourse than the bite, especially if there have been no reactions beforehand. on the part of humans or if the data previously received were not conclusive.
It is also difficult to know if sharks are able to memorize the man on the basis of one or a few encounters and to remember it (without repetitive daily conditioning, such as the artificial environment and the sedentary sharks in contact with the sea. man every day, several times a day).
Take the example of “human-eating sharks”. This name transposed to sharks comes to us from felines and wolves that eat humans. From a purely naturalistic point of view, in the history of hominids, our ancestors hid in trees and caves to protect themselves from prehistoric felines and canids. It has gradually become inscribed over thousands of years in the genetic code of these predators that hominids are potential prey. There are several factors that come into play, but a feline would make a decision about a human more quickly than a shark would. It is therefore completely normal to find today cases of lion or man-eating tiger. We can almost speak here of heredity.
Now let's apply this theory to sharks. The human activities on the seas and oceans mark a clear change of frequency since the second half of the xxe century. Despite the increased frequency of encounters between humans and sharks (all marine environments combined), they remain far too weak to allow sharks to equate humans with a potential source of food. No shark-friendly hunt strategy has allowed them, in such a short time, to acquire the information that could be included in their diet. This is evidenced by the number of incidents against humans each year compared to the number of human / daily shark interaction (more than 50 000 interactions each day). Biologically, this theory of the man-eating shark does not work either! Sharks must maintain a variable metabolic energy rate by eating approximately 10% of their weight every 10 days. If a shark had a special appetite for human flesh, we will see many more incidents against our species all over the world. Science has shown that between 1 000 and 35 000 years, it is necessary for a predator to assimilate and memorize new prey in its genetic code in order to understand how to successfully hunt it (this does not exclude a few successful attempts on animals not part of the diet of the species).
To demonstrate my words, let's take the example of the artificial invasion of lion fish or lionfish (Pterois volitans) in the Caribbean Sea. Local actions and businesses are trying to teach gray Caribbean sharks (Carcharhinus perezi) to feed on these fish which destabilize the local food chain. As they do not evolve in the same seas, lionfish do not appear in the genetic code of predators in the region. In this specific case, sharks react to stimuli when the scorpionfish is harpooned (wriggling, bleeding, sound) with a speargun. In some sites, sharks are sedentary, and over time should gradually assimilate lionfish to prey in the ecosystem in which they live. However, it has been observed that sharks never attack them if they are in good health. They will always prefer to take the easy opportunity to tackle the distressed lionfish. Even though lionfish have shared the ecosystem of the Caribbean gray sharks for about fifteen years, this time is not enough for them to understand how to hunt them effectively and therefore to integrate them into their genetic code as potential prey. This is where we encounter the problem of memory. Even if a shark eventually succeeds in hunting these fish, how is the transmission of knowledge to the juveniles, knowing that there is no learning by the parents? Epigenetics could be the answer but has never been proven in sharks.
Could we speak here of hereditary memory based on long-term learning? Studies contradicting the example given above, supplemented by empirical observations, have shown that sharks each have their own unique personality. This personality is based on the character traits of each individual, which like a litter of dogs from the same mother, we will observe shy, curious, daring, etc. Much of the individuality of animals with a developed cognitive system comes from lived experiences and very clearly demonstrates memory and the ability to learn, retain and reproduce through this memory. But where does this individuality come from in sharks? Is it genetically transmitted? Does it have a link with hereditary memory or intelligence? Or is it totally random?
In Bimini, Bahamas, it has been proven that juvenile lemon sharks (Negaprion brevirostris) of the same age are divided different roles and different spaces of evolution in the same community whereas they have only a few days! Sharks from the same mother will risk in dangerous areas but rich in fish (making the survivor stronger - dominant potential), while others will simply stay in the mangrove shelter from predators, but in a zone less rich in prey. These genetic predispositions allow natural selection. These juvenile lemon sharks demonstrate hierarchical socialization, know how to hunt (alone or in groups), protect themselves and react to the same situations that adults face, without having received an apprenticeship from their parents. This proves that this long-term memory is innate, acquired from birth and genetically transmitted and not learned. Instinctive memory seems hereditary.
How to prove that sharks are able to remember and memorize human activities? The act of repetition could in some cases "condition" sharks. It is not impossible that sedentary or constantly exposed individuals eventually develop a recognition system linked to stimuli. This does not imply that this information is transmitted genetically, nor that the shark will remember it if the frequency of the stimulus ceases or decreases.
In scuba diving I have often been confronted with the observation of the same individuals. How many times have I been charmed by the idea that they recognize me ... Yet at each meeting, the shark used the same interaction codes as the previous times. Is it mistrust of me, is it curiosity, or is it just the way a shark works with an animal unknown to its genetic memory? I like the example of Scarboard, this big female white shark (Carcharodon carcharias) 5 meters with which I had the chance to dive several times out of cage. This female, curious but cautious, takes about forty minutes to feel comfortable in the presence of divers. Beforehand, she performs any type of approach at various distances, from different angles, adopting different observation strategies, intimidation towards divers. Once the necessary information has been received and analyzed, feeling completely comfortable in the presence of the divers that she no longer considers as a potential danger (animals unknown to her genetic code), she allows herself several passes at a short distance, then displays clearly a dominant body language. We get out of the water, wait three hours and we re-immerse. It will take Scarboard exactly the same approach time of about forty minutes and even three hours later to assert itself again. As if the RAM of what just happened had been erased, like when you turn off a computer.
Another example ... In Egypt during the high season oceanic sharks (Carcharhinus longimanus), I sometimes observe in one day the same ten individuals on my three distinct dives. Each of them responds to the sound stimuli generated by the plastic bottle that I crack and sometimes comes to contact. No one will have learned from one dive to another, or from the beginning of the dive to the end of the dive, that this sound is only a subterfuge and not a prey in distress. They will return systematically along the same axis guided by the same instinct as their sense of hearing. This analysis was made in time over nine weeks of observation with the same sharks.
The boats represent sources of visual, sound, olfactory and vibratory catalysts very strong, which stimulate the interest of the sharks. However, here we must avoid shortcuts to Pavlov's reflex. Most of the sharks attracted to the boats are pelagic sharks that can not be packaged. On artificial feeding grounds, sharks may however be more prone to packing.
As you can see, quantifying the intelligence, cognition and memory of sharks is not easy. The few studies conducted directly on the brains of sharks in an artificial environment have demonstrated reflex behaviors related to stimuli. Unfortunately, because of the invasive nature of the techniques used which caused the immediate death of sharks after the experiments, knowledge about the development and understanding of the actions of sharks is now limited. Initiative, memory, decision? Or is it simply this ability to act and not think that would have saved sharks through millions of years? Even if experiments in an artificial environment have proved a possible memory related to conditioning over time, how does this cognitive system work in a natural environment? Is adaptation based on reflexes to stimuli or hereditary memory the key that will allow us to see the underwater world as sharks see? Or are we doing the wrong thing by still showing arrogance and wanting to systematically classify the actions of sharks by anthropomorphism?
We rely on ethological studies done on other animals and interpretations according to our logic, according to our earthly gaze and it is very likely that the answers to these questions will not be discovered for a long time. The real mystery may not lie in the will to understand, but in the ability to want / be able to resolve these issues. Perhaps, as with our place in the Universe, we would not be “equipped” and we would not have the intelligence to understand sharks in this complex environment that is the Ocean. At the same time, how do we humans interpret the presence of sharks in this universe unknown to our senses and instincts? Do we have the necessary equipment to understand them? To meditate…
Article by Steven Surina,