Animal brains v human brains – let the Battle of the Brains commence!

Think humans have the best brains out there? Yes, we’re pretty smart, but there are animals whose brains have evolved some incredible adaptations.

20th October 2017
Animal brains v human brains – let the Battle of the Brains commence! © Getty

Humans are widely assumed to be the most intelligent species on Earth due to our intricate civilisations and innovative behaviours. But, have you ever considered that our brains have features that are inferior to animal brains? We’ve pitted humans against the rest of the animal kingdom in various categories to reveal whose has the best cerebellum, the brightest cerebrum, and the greatest grey matter in the ultimate Battle of the Brains.

Smell

Unsurprisingly, humans won’t receive any awards for our sense of smell. While our brains are relatively large compared to most other animals, the part of our brains devoted to smell, the olfactory bulb, is comparatively small. The olfactory bulb of sharks occupies a staggering two-thirds of their brains, the largest of which belongs to the great white shark. Meanwhile, two rodents (agouti and capybara) have the largest olfactory bulbs of mammals, with another powerful rodent, rats, employed to sniff out land mines with extraordinary accuracy. Potentially the land animal with the best sense of smell are bears, with an olfactory bulb five times bigger than humans’, despite their brains totalling just a third of ours.

However, the exceptional sense of smell many species possess is not only due to differences in brain anatomy, but also a result of adaptations to their noses. With this sense, it’s less a case of which species surpass us, and more which species are even worse than us.

Navigation

We humans tend to pride ourselves on our exploratory and navigational prowess, but we never contemplate how we would cope without maps and, more recently, sat-navs. However, there is an animal that can find its way home from thousands of kilometres away without resorting to Google Maps: the unassuming pigeon. How can this be possible? After much debate, biologists have uncovered their secret - a collection of cells in the pigeon’s brain that respond considerably to magnetic stimulation. Each brain cell in the group responds with a unique signalling pattern to a particular magnetic field intensity, which the pigeon is able to interpret. Pigeons harness this power to detect changes in the Earth’s magnetic field dependent on location, decoding the signals to determine their exact geographical position. Therefore, if scientists started a human v pigeon race home from far away, the pigeon would undoubtedly cross the finish line first while the human wandered around trying to find a GPS signal.

Photographic memory

A substantial number of human children have a photographic memory, also known as eidetic imagery. This enables them to memorise large amounts of information when exposed to it for just a short period of time, but unfortunately this miraculous talent fades as the individual ages. Chimpanzees also possess this impressive eidetic memory, which dwindles with age in a similar way to humans’.

When this remarkable working memory was examined, challenging humans against chimpanzees, young chimpanzees were found to have a superior ability to retain a sequence of numbers than human adults. It was even found that the time the chimpanzees were exposed to the numbers did not affect their memory of them, suggesting the memory capture was almost instant. However, to really crown the champion of this battle, young chimpanzees should face human children and adult chimpanzees should take on adult humans, to account for the decline of eidetic memory with age.

Anti brain damage

Traumatic brain injury is the biggest risk to people under 40 in England and Wales, indicating humans lack efficient mechanisms to avoid this fate. Conversely, woodpeckers have evolved plenty of adaptations to prevent brain damage despite smashing their heads against trees at 6m/s up to 12,000 times a day. One adaptation is a thick skull layered with closely woven strips of bone forming a mesh-like structure that absorbs the shock of the impact.

Woodpeckers possess another shock absorber - a band of bone (the hyoid bone) surrounding their skull like a seatbelt.  Additionally, woodpeckers’ brains themselves are modified; they are longer than they are wide, spreading the impact force over a greater surface area. Moreover, unlike human brains, there isn’t much space between the skull and brain of woodpeckers (known as subdural space) to prevent the brain colliding with the skull. With all these inventive adaptations, woodpeckers would defeat any rock star in a head-banging showdown.

Brain Size

The enlarged foreheads and skull capacity of humans has enabled our brains to grow in size dramatically from that of our ancestors. However, it is still not the biggest brain in existence. Thrashing the measly 1.2kg human brain are the following species: dolphins at 1.5-1.7kg, elephants and blue whales at 5kg and killer whales at roughly 6kg. But, the biggest brain of them all is the sperm whale’s, weighing a mighty 7kg.

 

Many dispute the relevance of this, arguing that a brain-to-body mass ratio is more informative of intellect. Taking this into account, we would still lose; in this instance to the treeshrew because this humble creature has the greatest brain-to-body mass ratio of any species. So, in whichever way you pitch the battle of brain size, we still don’t reign victorious.

More glia (supporting brain cells)

There are two major cell types in the brain: neurones, the more widely recognised brain cell, and glia, the lesser-known brain cell. Neurones transmit messages containing complex information through and out of the brain, which lead to outputs by the body such as muscle activity. Glia are the supportive cells of neurones, helping to dispose of their waste and feed them vital nutrients and signalling molecules.

Arguably one of the cleverest humans, Albert Einstein, had a higher ratio of glia-to-neurones (i.e. more glia) than that of the doctors’ brains his was compared to. Furthermore, animal studies determine that, as intellect rises, the glia-to-neurone ratio also increases. Therefore, an indicator of brainpower could be an individual’s glia-to-neurone ratio, possibly because each neurone receives more glial attention and so operates more efficiently. If this were deemed an accurate measure of intelligence, the Minke whale would be the smartest species, having the highest glia-to-brain ratio of any species – 5.5 times greater than humans’.

Neocortex (complex processing)

Neocortex literally means ‘new outer layer of organ’ and describes the outer portion of the brain that evolved most recently. Only possessed by a few intellectually advanced species, the neocortex controls complex functions such as conscious thought, language and self-awareness. Although the human neocortex is the largest, the dolphin’s is more elaborately folded resulting in a larger surface area, a distinct mark of increased processing ability. This demonstrates two parallel, but possibly equally potent, methods of mental processing, suggesting that humans and dolphins are of fairly equal ability in some higher-order tasks.

Nevertheless, it has been proposed that dolphins have more sophisticated social relationships and speeds of perception, potentially due to their marine habitat and increased social reliance. In this particular battle, it would probably conclude in a draw, but with further research underway, this may not always be the result.

Neurogenesis

Neurogenesis is the process of making new neurones, a type of brain cell. Neurogenesis occurs at a remarkable rate during development, but by adulthood this process is restricted to the regions of the brain responsible for memory and sense of smell. That is, in the human brain. The same limitation is true of other mammals, however many non-mammals exhibit neurogenesis in other brain areas as well. The most extensively studied example of this is a large group of bony fish, the teleost fish group.

Teleost fish perform neurogenesis at an astonishing rate up to 100 times higher than mammals, even during adulthood. Neurogenesis is used to replace damaged or lost brain cells and increase the total number of brain cells. Therefore, this process is an extremely useful tool to enhance the population of neurones an organism possesses. Humans fall considerably short in this capacity, meaning we lose this brain battle to 96 per cent of fish, species such as anchovies, sea horse and carp.

Infrared Sensitivity

We perceive heat through our sense of touch, which informs the brain at a basic level if something is hot or cold. Some snakes have a far more sophisticated heat-detection system that involves utilising infra-red light, the wavelengths of light beyond red on the electromagnetic spectrum. The infrared-sensitive snakes have pit organs, holes filled with heat-sensitive nerves located below their eyes. They also possess a brain area not present in other animals that decodes the information from pit organs and translates it into a heat map. This heat map is sent to the specialised brain region that stores visual information, and is then superimposed over the snake’s visual map of its surroundings. This enables the infrared-sensitive snakes to view their environment in two ways simultaneously, building a more detailed representation of their setting than humans could ever imagine, let alone recreate themselves. 

Human victory

Despite all of the battles that we would lose to a fellow member of the animal kingdom, there are a whole host of cognitive abilities which are uniquely human, that no other animal could contend with. All of the following behaviours, as well as many other imaginative concepts, have currently been demonstrated exclusively in humans:

  • Advanced planning and decision-making
  • Humour
  • Appreciation of mortality
  • Adaptation to unsuitable environments (e.g. deserts and frozen lands)
  • Morality
  • Religion and worship
  • Vulnerability to neuropsychiatric disease
  • Enhanced connections between neurones
  • Non-personal comprehension

Remember, this is only the current outcomes of these brain battles - research is continuously being conducted which unveils ever more about the complex behaviours of other animals. Who knows, in the future, in discovering more about our animal neighbours, we may learn that our brains are not so special or superior after all.

 


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