Otter belongs to Chordata, Mammalia, Carnivora, Mustelidae and Otter. So the otter is a mammal. As a mammal, otters have some key characteristics that fit the basic characteristics of mammals.
One of the most important characteristics is the way of reproduction. Like most mammals, otters reproduce viviparously, with a gestation period of a few months before giving birth to their young. In addition, otters also have a lactation period, the mother otter will give milk to the newborn otter, it is clearly a mammal. In addition, otters breathe in the same way as most mammals, using lungs to breathe, so otters can not continue to stay in the water when breathing, but need to come out of the water to breathe. Moreover, as a mammal, otters are also a relatively advanced animal, they are more intelligent, relatively high IQ.
When otters grow up, their body length will generally be between 0.5 and 1 meters, and their weight will be between 3 and 20 kilograms, which is not particularly large. However, some otters are much larger than this, and their body length can reach more than 1 meter or even more than 2 meters. In the relevant records, there is an otter with a body length of 2.4 meters, which can be said to be the largest otter in the world. Such a large otter is very fierce, attack ability is relatively strong, they can even be recognized as very fierce crocodile easily defeated.
