Friend

The Bengali word “bondhu” (friend) originated from the word “bondho.” One meaning of “bondho” is “closed,” while another meaning is “bond” or “tie.” That is, someone whose thoughts are bound with yours becomes your friend. Friendship isn’t exclusive to humans; it has been observed among many animal species as well. The primary condition for any creature to easily consider another as a friend—regardless of species—is the absence of a sense of discrimination between itself and the other in its brain. This absence of discrimination fosters a bond between the minds of both beings.

Though the lack of discrimination is easily noticeable among members of the same species, it’s not rare among different species either. For example, dogs easily become domesticated and befriend humans. One reason why dogs so readily become human friends is the similarity between the structure and functioning of the dog’s brain and the human brain. The structure and functioning of an adult dog’s brain closely resemble that of a three to five-year-old human child. This is why when a pet dog dies, people usually get another; someone who has once owned a dog can hardly live the rest of their life without the companionship of a dog. Another important reason for this easy friendship is the “prefrontal cortex” of the dog’s brain (which is situated at the front end of the outer layer in the brains of nearly all mammals). You might find it amusing to know that a dog’s prefrontal cortex is so incapable of distinguishing itself from humans that dogs think of humans as fellow dogs throughout their lives, making them such great friends to humans! However, even though monkeys are evolutionarily closer to humans, domestication is much harder, because the prefrontal cortex in monkeys is quite aware of the difference between themselves and humans!

Just as various mammals can become friends with humans, so can different birds. However, while this depends on the prefrontal cortex in mammals, in birds it depends on a part of their brain called the “nidopallium caudolaterale” (which is located at the front end of the outer layer in the brains of almost all birds).