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Number of neurons in the brain of animals

The number of neurons in animals – Top 10

It is estimated that the human brain, with a mass of one and a half kilograms, consists of almost 90 billion neurons, but does man have the largest number of neurons in the brain? It turns out that it is not the man who has the largest number of neurons, but the elephant. Man in turn has the largest number of neurons in the cerebral cortex (10–20 billion neurons). Below we present a table containing over 100 animals with the largest and lowest number of neurons in the brain.

Animals – the number of neurons in the brain


Animals – the number of neurons in the brain

NoAnimalNeurons in the brain
1.African elephant  257 000 000 000
2.Human    86 000 000 000
3.Gorilla    33 400 000 000
4.Orangutan    32 600 000 000
5.Chimpanzee    28 000 000 000
6.Yellow baboon    10 950 000 000
7.Giraffe    10 750 000 000
8.Brown bear      9 586 000 000
9.Rhesus macaque      6 376 000 000
10.Greater kudu      4 910 000 000
11.Lion      4 667 000 000
12.Striped hyena      3 885 000 000
13.Bonnet macaque      3 780 000 000
14.Tufted capuchin      3 691 000 000
15.Crab-eating macaque      3 440 000 000
16.Common squirrel monkey      3 246 000 000
17.Blue-and-yellow macaw      3 136 000 000
18.Blesbok      3 060 000 000
19.Springbok      2 720 000 000
20.Dog      2 253 000 000
21.Domestic pig      2 220 000 000
22.Raven      2 171 000 000
23.Kea      2 149 000 000
24.Raccoon      2 148 000 000
25.Sulphur-crested cockatoo      2 122 000 000
26.Capybara      1 600 000 000
27.Grey parrot      1 566 000 000
28.Rook      1 509 000 000
29.Three-striped night monkey      1 468 000 000
30.Emu      1 335 000 000
31.Tanimbar corella      1 161 000 000
32.Alexandrine parakeet      1 096 000 000
33.Eurasian jay      1 085 000 000
34.Western jackdaw        968 000 000
35.Northern greater galago        936 000 000
36.Common hill myna        906 000 000
37.Magpie        897 000 000
38.Black-rumped agouti        857 000 000
39.Cat        760 000 000
40.Rock hyrax        756 000 000
41.Azure-winged magpie        741 000 000
42.Monk parakeet        697 000 000
43.Barn owl        690 000 000
44.Eastern rosella        642 000 000
45.Common marmoset        636 000 000
46.Western tree hyrax        505 000 000
47.Octopus        500 000 000
48.European rabbit        494 200 000
49.Common starling        483 000 000
50.Prairie dog        473 940 000
51.Banded mongoose        454 000 000
52.Gray squirrel        453 660 000
53.Cockatiel        453 000 000
54.Ferret        404 000 000
55.Common blackbird        379 000 000
56.Cape dune mole-rat        361 000 000
57.Budgerigar        322 000 000
58.Pigeon        310 000 000
59.Common treeshrew        261 000 000
60.Gray mouse lemur        254 710 000
61.Guinea pig        240 000 000
62.Green-rumped parrotlet        227 000 000
63.Great tit        226 000 000
64.Red junglefowl        221 000 000
65.Eastern mole        204 000 000
66.Guyenne spiny rat        202 000 000
67.Brown rat        200 000 000
68.Damaraland mole-rat        178 000 000
69.Mechow’s mole-rat        174 000 000
70.Cape mole-rat        170 000 000
71.Goldcrest        164 000 000
72.Four-toed elephant shrew        157 000 000
73.Eurasian blackcap        157 000 000
74.Silvery mole-rat        148 000 000
75.Star-nosed mole        131 000 000
76.Zebra finch        131 000 000
77.Eastern rock elephant shrew        129 000 000
78.Hairy-tailed mole        124 000 000
79.Mashona mole-rat        113 000 000
80.Ansell’s mole-rat        103 000 000
81.Golden hamster          90 000 000
82.Nile crocodile          80 500 000
83.House mouse          71 000 000
84.Hottentot golden mole          65 000 000
85.Short-tailed shrew          52 000 000
86.Smoky shrew          36 000 000
87.Naked mole-rat          26 880 000
88.Frog          16 000 000
89.Adult zebrafish          10 000 000
90.Cockroach            1 000 000
91.Honey bee               960 000
92.Fruit fly               250 000
93.Ant               250 000
94.Larval zebrafish               100 000
95.Lobster               100 000
96.Amphioxus                 20 000
97.Sea slug                 18 000
98.Pond snail                 11 000
99.Medicinal leech                 10 000
100.Box jellyfish                  8 700
101.Megaphragma mymaripenne                  7 400
102.Jellyfish                  5 600
103.Caenorhabditis elegans(roundworm)                     302
104.Ciona intestinalislarva (sea squirt)                     231
105.Asplanchna brightwellii (rotifer)                     200
106.Sponge                       0
107.Trichoplax                       0

Number of neurons in the brain of animals

The number of neurons in the brain of animals varies greatly depending on the species. For example, the brain of a honeybee has around 960,000 neurons, while the brain of a mouse has around 71,000,000 neurons. In comparison, the human brain has an estimated  86,000,000,000 neurons. However, it is important to note that the number of neurons alone does not determine intelligence or cognitive abilities. The way in which the neurons are connected and the complexity of the neural networks are also important factors.

In addition to the species, the size of the brain also plays a role in the number of neurons it contains. For example, the brain of a sperm whale is the largest known brain in the animal kingdom, weighing in at around 8 kg. On the other hand, the brain of a shrew, which is one of the smallest known mammal brains, weighs around 0.02 grams and contains around 36 million neurons.

Another example is the brain of an elephant which has around 257,000,000,000 neurons, which is more than any other mammal, however it’s often said that they have a “small brain” in comparison to their body size, it’s not a fair comparison.

It’s important to note that simply counting the number of neurons in an animal’s brain is not the only way to measure intelligence or cognitive abilities. Other factors, such as the complexity of neural connections and the ratio of brain size to body size, also play important roles in determining cognitive abilities.



Synapses are the specialized structures that allow neurons to communicate with each other and transmit information throughout the brain and nervous system. Synapses are formed when the axon of one neuron makes contact with the dendrites of another neuron. At the point of contact, a small gap called the synaptic cleft separates the two neurons. When a neuron is activated and generates an electrical impulse, chemicals called neurotransmitters are released into the synaptic cleft. These neurotransmitters cross the cleft and bind to receptors on the dendrites of the receiving neuron, causing a change in the electrical charge of the dendrites and transmitting the impulse to the next neuron.

The number of synapses in the brain is much greater than the number of neurons. It is estimated that the human brain contains about 100 trillion synapses, which is about 1,000 times more than the number of neurons. The number of synapses can also vary depending on the individual and the level of experience, plasticity, and learning.

It’s important to note that the number of synapses alone is not the only factor that determines cognitive abilities, the strength and efficacy of the synapses, the number of neurotransmitters released, the receptors and the neural networks also play crucial roles in determining the cognitive abilities.


What determines the intelligence of animals – brain size, number of neurons, number of synapses, or something else?

The determination of intelligence in animals is a complex and multifaceted issue and there isn’t a single factor that can be used to determine the intelligence of animals. However, some factors that are commonly considered when trying to understand intelligence in animals include:

  • Brain size
    The size of the brain is often used as a rough indicator of cognitive abilities, with larger brains generally thought to be associated with more advanced cognitive abilities.
  • Number of neurons and synapses
    The number of neurons and synapses in the brain is also thought to play a role in determining cognitive abilities, as a larger number of neurons and synapses would allow for greater complexity and processing power.
  • Neural connections and complexity
    The complexity and organization of neural connections and networks are thought to be important factors in determining cognitive abilities, as a more complex and interconnected network of neurons would allow for greater flexibility and adaptability.
  • Enzyme and hormone levels
    Some studies have shown that the levels of certain enzymes and hormones in the brain can also play a role in determining cognitive abilities, as they are related to learning, memory, and decision-making.
  • Evolutionary history and adaptation
    The evolutionary history and adaptation of a species can also play a role in determining cognitive abilities, as certain species have evolved specialized cognitive abilities to adapt to their environments.

It’s important to note that intelligence is a complex and multifaceted phenomenon and cannot be reduced to a single factor or a specific measurement. It also varies greatly between species and even within a single species.


Do more intelligent people, with a higher IQ, have a bigger brain, a greater number of neurons, or a greater number of synapses, than less intelligent people?

There is a correlation between brain size and intelligence, but it is not a direct cause-and-effect relationship. Studies have shown that on average, people with higher IQ scores tend to have slightly larger brain volumes, but there is a lot of variation in brain size within any given IQ range. Additionally, brain size alone is not a good indicator of intelligence, as other factors such as the complexity of neural connections and the organization of neural networks also play important roles in determining cognitive abilities.

The number of neurons and synapses in the brain is also thought to be related to intelligence, but again, it is not a direct cause-and-effect relationship. It is estimated that the human brain contains about 86 billion neurons and around 100 trillion synapses. Studies have shown that the density of neurons and synapses in certain regions of the brain, such as the cerebral cortex, is related to cognitive abilities, but again, there is a lot of variation within any given IQ range.

It’s important to note that while there may be some correlation between brain size, number of neurons, number of synapses and intelligence, these factors alone do not determine intelligence. Intelligence is a multifaceted and complex phenomenon that cannot be reduced to a single measurement. It is also influenced by a variety of factors such as genetics, environment, and experiences, and it may change throughout a person’s lifetime.

Some studies suggest that smarter people have bigger and faster neurons.


Questions for discussion – what do you think

  • Since man has fewer neurons than an elephant, is he smarter than an elephant or not?
  • If man is smarter, what determines intelligence?
  • Do all humans have a similar number of neurons?
  • Do people with a higher intelligence quotient (IQ) have:
    • more neurons
    • more synapses
    • more neurons and synapses
    • have the same number of neurons and synapses as people with a lower IQ
  • Does the number of neurons decrease with age, or does it increase?
  • At what age does man have the most neurons?


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One Comment

  1. Interesting information!
    I was looking for information regarding the horse and/or zebra, which unfortunately aren’t in this list although the dog and cat are. Understandable, as including all species would be impossible.
    Since Giraffes have a similar body and brain weight as well as living strategy to horses, I guess that’ll
    have to do!

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