Dolphins are recognized as the most human-friendly marine animals. They are often spotted in the fog, guiding ships and helping sailors navigate safely.
If someone falls into the water in the ocean and encounters sharks or other fierce fish, they would likely not survive. But if they were lucky enough to encounter dolphins, the dolphins may come to their rescue in droves.
Dolphins are a collective name for a class of aquatic mammals in the dolphin family. They are small or medium-sized toothed whales and are widely distributed in the world's oceans.
They can also be found in inland seas and rivers near the mouth of salt and fresh water. Some individual species are even found in inland rivers. They usually prefer to live in groups and prey on fish and squid.
Dolphins mainly inhabit warm waters in the tropics, but some species, such as the open-spined dolphin, prefer colder waters. They typically live in shallow waters or at least stay near the surface.
Compared to other cetaceans, dolphins do not dive as long or deep. They are fast swimmers and have acrobatic characteristics. The "dolphin swim" is a unique swimming style where the entire body leaps out of the water at a small angle and then re-enters the water at a small angle, which distinguishes them from other cetaceans.
Dolphins are swift swimmers, usually reaching a maximum speed of about 30-40 km/h. Some individual species can exceed 55 km/h and can maintain their speed for a long time, making them the long-distance swimming champions of the ocean.
Some dolphins are highly social species, living in large groups consisting of sometimes more than 100,000 individuals. They exhibit many interesting collective behaviors, including cooperating with each other to attack sharks and rescue injured or sick individuals.
Groups of dolphins often follow boats on the waves, making spectacular acrobatic leaps into the air.
Dolphins are highly intelligent and have well-developed brains with many grooves. The more grooves, the more developed the intelligence.
The average brain weight of an adult dolphin is 1.6 kilograms, slightly larger than that of the human brain, which weighs about 1.5 kilograms. In comparison, the average weight of the brain of an orangutan is less than 0.25 kilograms.
From the absolute weight, dolphins have the largest brain, but from the ratio of brain weight to body weight, the human brain accounts for 2.1% of body weight, while dolphins account for 1.17% and orangutans only 0.7%.
An oceanographer found that dolphins have their own language, and he recorded the various calls of dolphins for research. He discovered that dolphins can use their own voice to convey messages and can also understand the meaning of some artificial sounds. Additionally, the dolphin's unique call signal can also be linked with their companions.
The number of grooves in the brain is a basis for judging the development of intelligence. The more grooves, the more developed the intelligence. Because the dolphin brain is very rich in grooves, dolphins are considered smarter than orangutans, with an IQ value higher than the average value of 45 to 70, estimated to be around 60.
