What has the largest brain in comparison to its size?

Question

What has the largest brain in comparison to its size?

Answer 1

Any brain is whatever size it is. How do you compare something  to itself?

Answer 2

Humans.

Answer 3

do you mean: What has the largest brain in relation to its size?

Answer 4

a brain in a vat

Answer 5

mammals it is dolphins not us humans. Due to the amount of computing power for their echo sonar and complex squeak language.

The biggest ratio of all in brain weight to body size are male canary's, possibly to increase computing speed of songs sung.

Answer 6

Humans have the largest brain weight to body weight ratio of any creature, and that is significant because that is about the only way that the human brain could possibly be considered superior to the cetacean brain.

The cetaceans (whales, dolphins and porpoises) developed brains about the size and complexity of ours about 30 milliom years ago, about the time that Australia and Antarctica began to drift apart, and all of the surviving cetaceans are descendants of that large-brained whale.  That means that all of the cetacean brains are literally 30 million years more highly evolved than ours.

The most primitive brain in the Order Cetacea belongs to Eschrichtius robustus, the Pacific gray whale, but interestingly enough, that brain has almost exactly the same neuronal density, the same number of neurons per cubic millimeter as our brains.  But gray whale brains are four times bigger than ours, and if positioned as though the whale was standing on its tail, look like nothing so much as human brains on massive steroids.

When it comes to brains, size doesn't cut it at all.  The three higher cortexes that cover our brains are each only three layers of single cells thick, yet those layers are the essential difference between humans and lizzards.  All of the Cetaceans have three complete cortexes of three layers each except killer whales (Orcinas orca).  They also have three complete cortexes, but covering about 2/3 of their brains is the first layer of a fourth cortex.

In human brains, we know that the more surface area the the higher cortexes have, the more folds and ridges the brain has, the smarter the individual is likely to be.  Orca higher cortexes have nine times the surface area of human brains.

We don't know exactly what this fourth cortex does, but we do know that it's an association cortex, it's a thinking machine.  Killer whales can conduct five to eight conversations at a time using three separate voice boxes at the same time on different conversations, which would at least infer that they have multiple parallel processing mental capabilities, whereas we have pokey old serial processors.  This multiple parallel processing ability would logically translate into multiple-point consciousness or the ability to think about many unrelated subjects simultaneously.

Answer 7

I would guess the human, but most do not use it properly.