The brain is said to be the most complex organ in the body. It is the center of the nervous system in most animals and controls the other organs in the body. Much of the way that the brain functions is still a mystery to scientists. Interestingly, intelligence doesn’t really depend on the size of the brain. Most animals have a brain, from the very small to the very large, but which animal has the largest brain?
Largest brain by mass
The animal with the largest brain by weight is the sperm whale. The average full size sperm whale has a brain that is 9kg (about 20lbs). Although this is very big, it is only 0.02% of the total body mass of a sperm whale (the human brain is about 2% of our total body mass). This means that the sperm whale actually has quite a small brain in comparison with its body.
Largest brain in proportion with body
This question is a little harder to answer because of the different measurements. The shrew, a mouse-like creature, has a brain that is 10% of its body size. This makes it the animal with the largest brain to body ratio. However, humans are the leaders when it comes to Encephalization Quotient (EQ), which is a way to measure brain size based on actual and predicted brain size. This is considered to be the better measurement of brain size. The animal with the largest brain size on the EQ scale, after humans, is the Bottlenose dolphin.