Which Animal Has The Largest Brain?
Largest Brain = Most Intelligent?
Which animal has the largest brain? And you know it got me thinking - so that's a good start, my brain, the human brain uses reason, calculation, perception, speech, sound, taste, touch and sight to understand things.
We are considered a pretty intelligent species aren't we?
But then we would think that since the whales, ants and dolphins are not capable of writing a thesis to dispel that belief.
After all, don't whales have the biggest brains?
So this article considers the creatures, animals, mammals, birds and 'pods' to find out which animal has the largest brain and whether there is a correlation between brain size and intelligence or perceived intelligence in those creatures.
We All Came Out of The Sea, Right?
If you believe the Primordial Soup Theory, then we all started as 'life' in Earth's giant ocean.
So how do creatures from the sea feature in brain size terms?
Most people think the Blue Whale has the largest brain of all living things; in fact it is the sperm whale who is top of the league.
The Sperm Whale brain weighs about 17.5 pounds, so it outweighs the Blue Whale by 5 pounds.
However, the density of the sperm whale's enormous brain does not compare with that of dolphins.
Brain size in sea mammals has been studied over the decades and there is a measure for density known as encephalization quotient. The brain mass, it has been hypothesised determines how intelligent a creature might become, but this could never be proved.
However, sperm whales do communicate through clicking so they understand 'language' and they have innate patterns of behaviour which suggests levels of inbred intelligence.
However, the male of the species also regularly beach themselves in shallow bays and on beaches.
When examined, these beached sperm whales are often discovered to be mature males.
Mature sperm whales become quite solitary as they get older and this beaching behaviour suggests shared intelligence or instinct - mass suicide?
One theory has it that they are affected by destructive sonar noise from marine equipment and get the equivalent of the bends, making them flee or panic but we can never know the answer.
Dolphins and Killer Whales
Dolphins are considered to be one of the most intelligent creatures and their brain size is about 4 pounds.
When one looks at brain to body ratio, dolphins are just behind man and are considered the second most intelligent creature on earth.
Dolphins' extremely intelligent behaviour is thought to be a direct result of evolution.
Marine biologist, Lori Marino of Emory University has studied MRI scans of dolphins and determined from her findings that creatures evolve in accordance with their needs - e.g. a spider is as intelligent as it needs to be to survive, as is a rat.
The dolphin has developed in much the same way, learning that they needed to communicate more, they honed their communication skills.
Dolphins are very social creatures, interaction with other dolphins (and also humans) is something that they seem to enjoy (source - DiscoveryNews.com).
We have all seen amazing dolphin shows over the years and we are still awe struck by their funny little personalities or at least that's what it seems.
We need to remember killer whales are part of the same species as dolphins which might explain their own ability to do tricks and appear in marine shows, they are also very social creatures.
A killer whale's brain is not quite as heavy as a sperm whale's but its enchephilization quotient is denser, suggesting it is more intelligent.
A killer whale recently killed a trainer at Seaworld and nobody could understand its behaviour but as humans, we can only ever guess at what goes on in a killer whale's head - clever as dolphins but not called 'killer' whales for nothing, instincts are always present even when they are splashing teenagers at Seaworld with their big tails.
The Octopus, on the face of it, may seem an unassuming little marine creature but don't be fooled; this invertebrate is perhaps the most intelligent of all of the marine creatures, the octopus has the largest neurons (brain cells) in all of nature.
Consider this - a male octopus dies roughly six months after mating (always!) and the female usually dies a month or so after caring for their unhatched eggs - they actually don't eat during this care period, eventually by the time the eggs hatch, they die of starvation.
Consequently, baby octopuses learn nothing from their parents; they learn as they go, using sense and innate intelligence to survive. They are supreme defenders of themselves - squirting ink and also venom at predators.
In tests by marine biologists using mazes, octopuses learned how to get out of a maze and showed high levels of intelligence in all tests.
Oh and one of them predicted results in the World Cup Soccer a few years ago and got it right every time.
They might not have the largest brain but it works hard and they are undoubtedly intelligent.
Brain Size of Mammals, Primates and Other Land Based Creatures
Human beings brains weigh 2.7 pounds and our closest 'relative' on earth, the primate has a brain size of similar brain to body size.
The gorilla's brain is 0.95 of a pound in weight, whilst a chimpanzee's brain weighs in at 0.77 pounds. The smallest primate brain is that of the Mouse Lemur at 0.004 of a pound.
Primates have been studied for many years, often because of their obvious likeness to human beings and they show many signs of congitive ability - they hunt together, creat strategies for doing so which are shared. They are highly social creatures and communicate with one another effectively.
Tests done with chimpanzees show they can learn human language meaning and respond to it and have also shown some intelligence with symbols and numerical values. So over the years we have enjoyed seeing them in movies using facial expressions and making odd little noises, all apparently typical behaviour in the wild too.
The elephant, not surprisingly, has the largest brain of land-based mammals.
Elephants are thought to be intelligent creatures - recently an elephant was shown creating walter colour paintings at a zoo!
Elephants display grief and of course for many years, they worked in circuses.
They are also very social animals and are able to work together to move around for food, create societies, raise their children together and support and provide for one another.
The Shrew - Small But Perfectly Formed
The shrew, the small spiky toothed mole-like creature is unusual in the animal kingdom for having the greatest brain to body mass ratio - their brains represent 10% of their body size, this is greater even than human beings.
Shrews don't appear to have any super intelligence features. Unlike the other animals and mammals discussed in this article, they are not social creatures - they live and hunt alone.
They communicate by using echolocation, using a series of squeaks to discover something about their surroundings. They squeak at a certain pitch and intensity and the returning echoes of their squeaking tell them where they are in terms of relief of the land, hard or soft surfaces etc.
So the shrew, whilst appearing to have the brain size to suggest a hidden genius doesn't seem to demonstrate any intelligent behaviour outside of the norm. That said, whilst scientists have studied shews' bodies, blood and cells (and very useful they are too, revealing possible supports to treat ovarian cancer), their brains have not been studied to any great degree.
So what about our dogs and cats?
Dogs' closest wild equivalent the wolf has a brain typically 30% bigger than a dog (based on a dog of a similar size to a wolf). Anyone who owns a dog can tell you that they are intelligent creatures. They can be trained to do a great many things; maybe sitting when you tell them to "sit" or playing dead, much to the delight of visiting guests.
But let's remember they can also be trained to sniff out narcotics and were used extensively in world war one as messengers. They can herd sheep and hunt for small animals like rabbits. They have been used for a long time as guide dogs and more recently as 'hearing' dogs for the hearing impaired.
They truly have become man's best friend!
Dogs were thought to have been domesticated over 15,000 years ago. As puppies, they learn some behaviour from their parents but when they come into contact with human beings, they learn from humans. People will have heard of Pavlov's Dog - an experiment to show that humans could control the behaviour of an animal by using classical conditioning.
So dogs can learn behaviour from a variety of sources and they can also remember things very easily - don't their tails wag like crazy when they see you? Don't they know where their harness or lead is kept for walks? And they always seem to know when it is dinner time.
Pack Animals - Wolves
Wolves can also learn behaviour from their parents when they are born. They are very social creatures but have a hierarchy so that they know where they fit into their pack and what behaviour is acceptable for their place in this hierarchy.
Wolves are most famous for being excellent hunters and they hunt strategically, positioning themselves in certain patterns, undertaking certain movements and deliberately identifying the weakest prey in their sights. Wolves use their allegiances with one another to strengthen the pack.
They have been seen to try and open gates so seem to have some mechanical skills, an unusual trait in hunting animals.
Whether wolves can ever be tamed remains a mystery. Some people have taken them in from being pups, usually as a result of rescue and have claimed to have 'potty' trained them etc but no one would argue that dogs and wolves are different beasts.
Does your cat display its wilder side?
- 67% Yes, I am tired of disposing of mouse and bird 'offerings'
- 33% No, 100% pussycat!
This poll is now closed to voting.
Cats - Wild and Otherwise
Domesticated cats probably show more of their evolutionary sources than domesticated dogs.
A domesticated cat has a brain weight of 0.006 of a pound, almost 24% lighter than that of a wildcat. In scientific test on the brains of domestic cats, they were considered to be of low intellect but it has been determined over time that domesticated cats actually learn behaviour in a domesticated setting; they also show signs of memory retention.
However, they also love to hunt, to scavenge and are nocturnal creatures by habit.
The wildcat is famed for its hunting and scavenging and like a cat, has lightning speed and is a nocturnal creature too.
The domesticated cat, it seems, has kept some of its genetic blueprint from its wild cousin.
Tigers have the largest brains of the felines, but they live in an environment which requires cunning, bravery, speed and so on so is there a correlation between brain size and the environment ?
I think it is difficult to disprove this - we all evolve because of our surroundings - to enable us to survive; it is no different for animals, mammals, encephalopods, rodents etc, etc.
So does brain size matter? The answer seems to be "Yes, sometimes".
There is no evidence across the board for every creature to suggest that it is always the case
. Researchers will continue to discover new and amazing things about the intelligence of us and the creatures with whom we share the earth and oceans.
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