The brain size of a creature and that creature’s intelligence has been a topic of discussion among experts and the general populace for a while now. The weight or the volume, which is determined through skull volume or MRI scans, can both be used to measure the size of a brain.
The Animal With The Biggest Brain
The sperm whale has the largest brain in the world. Incredibly, the sperm whale has a brain that weighs around 18 pounds. This fact is not that hard to believe considering that the sperm whale (or cachalot) is the most enormous toothed whale, not to mention the fact that it’s the biggest toothed predator. The males are usually bigger than the females with an average length of a whopping 52 feet and an average weight of about 45 short tons. Females are slightly smaller with an average length of about 36 feet and an average weight of 15 short tons. Newborns are the smallest with a meager average length of 13 feet with their weights averaging approximately 1.1 short tons.
To put the size of the sperm whale’s brain into perspective, it is at least five times as large as human’s brain. Their brains have a volume of approximately 8,000 cubic centimeters. Despite their large brain size, the sperm whales have a lower encephalization quotient compared to plenty of dolphin and whale species. This low quotient means that the sperm whale is not necessarily the smartest creature on the planet. In terms of relative and absolute size, the whale’s cerebrum is unmatched in terms of size by any other creature on earth. The reduced olfactory system also translates to a poor sense of smell and taste. However, the auditory (hearing) system is inflated while the pyramidal tract is not that well developed.
Other Animals With A Big Brain
Interestingly, the animal with the second largest brain on earth is also a sea creature. The killer whale, more commonly known as the orca, is also a toothed whale of considerable size. In fact, in its family, the oceanic dolphin family, the orca is the most enormous of them all. Their brains’ weight averages between 12 and 15 pounds. Their intelligence is higher than most creatures even though it cannot be measured for certain. The idea that they are smart is more of a human perception.
The elephant is also another creature of immense size and a large brain. Elephant brains weight about 11 pounds. However, their large brains are proportionally smaller. When they are born, elephant brains already have about 30-40% of the weight they will have when the elephant reaches adulthood. The temporal lobes are extremely large with the cerebellum and cerebrum well developed. The bottlenose dolphin is also another creature that has a large brain. Their brains average between 3.3 and 3.7 pounds.
While brain sizes vary with size, the relationship is hardly proportional. In fact, the creature with the largest ratio is none other than the tiny shrew. Also, predators tend to have larger brains than their prey. The bigger the brain also means that the majority of the brain size is occupied by the cortex.