What do large animals do with their large brains?

Factual Questions
1

Human beings engage in some pretty complex behavior, attributable to having brains so big that the birthing process is rather difficult and hazardous to the mother’s health.

I’m no biologist, but ISTM that the complexity of behavior that is possible for any given brain would be related to the number of neurons (for which physical size ought to be a fair proxy) and the number of interconnections between those neurons. Gazing out over the animal kingdom, there are quite a few creates with larger brain mass than human beings. Rhinos, hippos, elephants, and whales come to mind immediately, though I’m sure there are others.

What do these large animals do with their large brains? If a human being can thrive on the savanna with a brain that weighs in at about 4 pounds, what is the elephant doing with its 11 pounds of intellect? Human beings and elephants both form numerous social connections, have long memories, cooperate to deal with environmental/predatory threats, use language, transmit culture to succeeding generations, and so on. But couldn’t elephants do this with the same 4-pound brain that we have? What about the blue whale, with its 15-pound thinker?

Do these animals demonstrate intelligence or complex thought that scales in any way with their much larger brains?

2

I’d guess that larger animals need bigger brains just to control all that mass/ surface area. Just think about the skin tactile/pain receptors on a foot - if you only have a tiny mouse foot you probably don’t need a whole lot of neurons dedicated to this to navigate the world, but if you have a foot with the surface area of an elephant, you’re probably going to need more.

Which is why intelligence is generally correlated with a higher brain-to-body mass ratio instead of purely brain size.

3

Yes, humans are very unusual in having so much thinky bits–brains are largely for feely bits.

4

Body mass to brain size is a crude measurement.

This formula puts humans comfortably ahead of other big brained species.

5

Here is an interesting article that relates.

6

Elephants at least have a highly developed social structure (there are some great books available that talks about it), so I think they use a lot of their brain mass for communication and memory.

We’re only beginning to plumb the depths of animal communication and intelligence, but what’s being documented so far is astonishing. I think the way we think about (and treat) various species is going to be completely upended in the next 20-50 years.

7

Does this mean that fat people are dumber?

8

Actually, it raises one interesting (to me) question. Fat people have more skin area. Do they have same total number of nociceptors as a thin person? Do they have the same total number of neurons in their brain dedicated to processing sensory input from the skin? If so, do they have a dulled level of dermal sensation, owing to the greater total skin area that’s being serviced by that fixed quantity of neural hardware?

9

So us average people can feel superior in some way to those with an excessively large penis?

10

“The number of neurons in animals of different sizes grows with the size of the brain but stays behind the volume of the brains. In fact, in small brains the neurons are packed more densely than in larger brains. In the mouse cortex there are about three to ten times more neurons per cubic millimeter than in the human brain. This is due to the proportion of volume occupied by the neuronal cell processes, which in larger brains tend to be longer for obvious geometrical reasons.”

http://www.scholarpedia.org/article/Brain#Size_and_weight_of_the_brain