pig

Facts have proved that the pig is actually a very clever animal, and it may be the smartest domesticated animal on earth. Although their primitive intelligence is likely to be comparable to that of dogs or cats, their ability to solve problems exceeds that of domestic animals such as cats and dogs.

Domestic pigs can quickly understand the working principle of mirrors and use their understanding of reflected images to observe the food around them. It is uncertain whether these pigs realize that the image in the mirror is themselves, or whether pigs can be juxtaposed with apes, dolphins and other species that have passed the famous mirror self-recognition test, but this has been regarded as a sign of self-awareness and advanced intelligence.

In an experiment in the 1990s, pigs were trained to move a cursor on a video screen with their noses and use the cursor to distinguish the graffiti they knew from the graffiti they first saw. They learn this task as fast as chimpanzees!

octopus

If pigs are the smartest domesticated species, octopus is the smartest invertebrate. Labyrinth and problem-solving experiments show that they have both short-term memory and long-term memory. Octopus can open cans, squeeze through small holes and jump around in cages to eat snacks. They can also be trained to distinguish different shapes and patterns. In an activity similar to a game, it was observed that octopus is a species with high intelligence. They repeatedly put bottles or toys into the aquarium and then catch them.

Octopus is the only invertebrate that has been proved to use tools. At least four specimens were witnessed to recycle discarded coconut shells, manipulate them and reassemble them for use as shelters.

crow

In many myths or fairy tales, the crow plays a shrewd liar, but in the real world, the crow has been proved to be a quite clever species. Crows discover specialties, such as the use of tools, the hiding and storage of food, the memory of scenes, and the ability to predict the future by personal experience.

Crows in New Caledonia will throw hard nuts into the streets full of cars and crush them. Crows in Queensland, Australia even learned how to eat a poisonous toad safely. They turned the toad upside down and stabbed it in the throat, because the poisonous skin of the toad's throat is the thinnest, and it can chew out non-toxic internal organs after stabbing it in.

Crows have the ability to recognize one person from another by facial features. They can remember people's faces for many years! So be careful when you see crows, and don't offend easily.

dolphin

Dolphins are one of the smartest animals in the animal kingdom, partly because they live a socialized life, and they are also considered to have a complex "language". Dolphins can learn a series of impressive behavior instructions from human trainers by using tools in the natural environment. Like many of the smartest animals on earth, female dolphins will live with their cubs for several years and teach them all the skills of dolphin survival. Dolphins can understand many things, and they also show their ability to recognize themselves, which is a sign of being the smartest animal.

elephant

Elephants are one of the smartest non-primates. They live in a closely related society with complicated social strata. Elephants also show altruism to other animals, and pregnant females have learned how to eat certain leaves to induce childbirth.

They can also use tools and adapt to the new environment quickly. Elephants also know that throwing a very big stone at the electric fence can destroy the fence and cut off the power supply. In order to get food, "elephants can learn to coordinate with their peers in a task that requires two people to pull both ends of the same rope at the same time to get rewards", which is on the same level as chimpanzees.

But what really sets elephants apart is their complicated death ceremony. Apart from elephants, humans and Neanderthals are the only animals known to pay tribute to the dead. Usually, while keeping quiet, elephants gently touch the bones of newly dead people with their noses and feet. Sometimes, elephants unrelated to the dead go to their graves.