How Big Is Our Human Brain Compared To Animal Brains?

How big is the brain of a human compared to the brain of an elephant? Or a whale? Or a mouse? Or an ant? Find out in this video!
Over the course of evolution the human brain has grown significantly and makes us the species we are. But how big is our brain compared to other animals?
The biggest brains in the animal kingdom belong to whales, sperm whales in particular. On land the elephant has the largest brain, which indicates that larger animals have larger brain. However, this is not always the case. Giant dinosaurs had relatively small brains.
Nevertheless, relative brain size is a better measure. Compared to body weight, tree shrews have the largest brain within the class of mammals. In general, ants have the largest brains compared to their body weight.
Still, even relative brain size seems not fair measure. That is why the encephalization quotient is often investigated. The encephalization quotient displays animal size and animal brain size on a logarithmic scale. Next a regression line is fitted. Animals above the line have larger brains than average, animals below the line have smaller brains than average.
So, using this encephalization quotient, who has small brains? Snakes, ostriches, chickens, giraffes and kangaroos have small brains within their respective class. Big brains belong to monitor lizards, parrots, corvids, dolphins, and primates. The largest encephalization quotient belongs to humans. But we should be careful to relate this to intelligence. Yes, encephalization quotient is related to intelligence, but this is not a perfect correlation. It just gives an indication.
Time stamps
0:00 The big brain of humans
0:40 Animals with the largest brains
2:10 Relative brain size of animals
4:22 Encephalization quotient
6:18 Encephalization quotients in reptiles
6:55 Encephalization quotients in birds
7:35 Encephalization quotients in mammals
8:18 Does encephalization quotient relate to intelligence?
References/resources:
Ashwell, K., & Gurovich, Y. (2019). Quantitative analysis of forebrain pallial morphology in monotremes and comparison with that in therians. Zoology (Jena, Germany), 134, 38-57. doi.org/10.1016/j.zool.2019.0...
Hurlburt, G.R. (1996). Relative brain size in recent and fossil amniotes :determination and interpretation. National Library of Canada (Ottawa, Canada), ISBN: 06121175109780612117518
Lu, J. S., Yue, F., Liu, X., Chen, T., & Zhuo, M. (2016). Characterization of the anterior cingulate cortex in adult tree shrew. Molecular pain, 12, 1744806916684515. doi.org/10.1177/1744806916684515
Sherwood, C.C., Stimpson, C.D., Butti, C. et al. Neocortical neuron types in Xenarthra and Afrotheria: implications for brain evolution in mammals. Brain Struct Funct 213, 301-328 (2009). doi.org/10.1007/s00429-008-01...
Video material:
www.pixabay.com
www.pexels.com
Footage of mice: UTAHnmaz (CZcams)
Footage of tree shrew: Small Mammals of Borneo (CZcams)
Footage of crow: PLOS Media (CZcams)
Footage of parrot: Times of India (CZcams)
Narrated by: Miles Wischnewski
USE OF STOCK IMAGES AND VIDEOS
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[@user-mo8he3bp1j]

But it also makes it easy to be mind fucked.

[@saptadipachakraborti6062]

How can we calculate the expected size of the brain relative to body mass???

[@real.psyched]

When plotting values of body size and brain size of a large amount of species on a logarithmic scale, your get a scatter plot. By performing a linear regression, you get a best fitting line, which represents the "expected" brain size. Though I should point out that the word expected should be seen as statistical terminology.

[@saptadipachakraborti6062]

@@real.psyched Is there any formula to calculate it?? Actually I've seen everywhere that EQ value is the ratio of actual brain size and the 'expected ' brain size of average mamal with same size.... So it's my only confusion that how can I calculate the expected size to also calculate the EQ of that species???? Plz clear it

[@real.psyched]

​@@saptadipachakraborti6062 When you have a regression line through all the observed brain sizes and body sizes in your scatter plot, the regression line has a certain y value for a given x value. If you then have the actual brain size of an animal. you can divide this value by the y value on the corresponding point of the regression line.
The specific value will differ for each study, but when going by study of Hurlburt from 1996. as an example:
EQ for mammals = Brain mass / [0.056 x (Body mass ^ 0.75)].
For birds and reptiles the formulas are different.

[@saptadipachakraborti6062]

@@real.psyched Thnk u so much....bt in case of EQ in mamals what is 0.02 which is Being multiplied by body mass?

[@real.psyched]

I don't understand what you mean with 0.02, but I would advice you to read the paper. There is a link in the description.

[@martijn2246]

interesting!

[@real.psyched]

Thanks Martijn! :)