A look at the most intelligent marine mammals: dolphins
Of all the aquatic mammals, dolphins are probably the most sympathetic in almost all cultures and geographies on the globe. Their presence in marine waters is always celebrated and welcomed, and their playful movements interpreted as a clear sign of intelligence, since these smiling-looking, smooth-bodied animals have a brain much more similar to that of primates than originally believed. .
Dolphins are, like the rest of the cetaceans, the result of evolutionary adaptation of terrestrial mammals (probably artiodactyls, related to modern hippos) that returned to marine life around 50 million years ago. However, when we talk about dolphins, we generally mean oceanic dolphins, that is, those that live in the seas (or in ponds, in captivity) and not their cousins who live in rivers and freshwater (the superfamily of platanistoids), with which they have important differences.
This means that dolphins are not related to fish, and in fact the latter constitute a large part of their strictly carnivorous diet. On the contrary, in the tree of life, dolphins are close to whales and orcas, and constitute their own family (Delphinidae) of about 37 known species. Broadly speaking, these animals have fusiform bodies, between 2 and 8 meters long, with an elongated snout and a blowhole on the top of the head, which serves as an opening for breathing. Dolphins do not have gills but lungs, but they are capable of holding their breath for up to 10 minutes underwater.
Regarding their habitat, dolphins are found in practically all the seas of all the oceans on the planet, although they tend to prefer the warm waters of the tropics. They are skilled swimmers and hunters, capable of swimming at speeds close to 50 kilometers per hour. And they also have the ability to emit a wide range of sounds, which they not only use to communicate with each other but also as radar, through echolocation. A sound wave is emitted that bounces against the environment and when it returns to the ears of the dolphin, it brings with it recognizable information. This is a very precise and unique location system for dolphins among marine animals.
The smartest marine mammals
What is most striking about dolphins is their degree of intelligence, comparable to that of a chimpanzee (or even a 3-year-old child). These animals are known to possess a high degree of sociability, which is why they are capable of hunting in packs, coordinating themselves through click-like sounds, hisses, and bursts of other sounds, similar to those they use for echolocation.
Dolphin pods can number up to 1,000 individuals, linked to each other by strong social ties, as evidenced by helping injured conspecifics rise to the surface to breathe, or assigning each other unique whistles to identify each other. in the middle of the herd This does not mean that there are no competitive dynamics, especially among males, and it is common for adults to display scars from fights over access to females or food.
Dolphins, however, along with humans and a few other primate species, are the only known animals capable of using tools to solve problems. In the Indian Ocean, they have been seen covering their snouts with sea sponges to protect them from rubbing against rocks as they rummage for food, a technique mothers teach their young.
Similarly, dolphins can form alliances with humans, either to face predators (such as certain species of sharks), or in exchange for rewards, as training. In fact, trained dolphins are used as part of the maritime military forces of some countries, and in numerous aquatic shows in which they play with balls or dance for the public. There have even been cases of cooperative fishing between humans and dolphins, spontaneously teaming up so that both species benefit.
Despite this, many human activities are harmful to dolphins, and a significant number of them die each year from injuries caused by ship propellers, or caught and suffocated in fishing nets. To this must be added that dolphins are part of certain Asian diets, such as in Taiji (Japan) or the Faroe Islands, and how sensitive these animals are to levels of maritime pollution with pesticides, heavy metals and other agricultural and industrial waste. . Dolphins have no natural predators. The damage to their communities and ecosystems is, for the most part, a consequence of human actions.
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