Which species has the largest brain relative to body size?
Quick Answer
Among animals, the sperm whale is one of the best-known examples of a very large brain, but humans have the largest brain relative to body size among the commonly cited mammals. Relative brain size is usually measured by brain-to-body ratio or encephalization quotient.
The Full Story
When scientists compare brain size relative to body size, humans rank exceptionally high among mammals, which is one reason our species is often highlighted in this category. Different methods can produce different winners depending on the animal group being studied. For example, birds such as crows and parrots also score very highly relative to their body size. Because the question depends on the exact metric, it is better answered as a matter of relative brain size rather than raw brain mass.
Key Facts
YouTube Angle
Suggested video title for this topic:
"The smartest brain is not always the biggest one!"