Support Provided ByLearn More

Ask Dave Your Questions

ByTom MillerThe Secret Life of Scientists and EngineersThe Secret Life of Scientists and Engineers

Receive emails about upcoming NOVA programs and related content, as well as featured reporting about current events through a science lens.

Click here for Dave’s Profile.

Dave Sulzer has some friends who weigh 10,000 lbs… EACH.

Support Provided ByLearn More

Q: George L.

Do elephants brains experience same problems humans do like strokes, seizures and are they able to multi-task or have a subconscious?

A: Dave Sulzer

George, glad you asked, though I have some reading to do and maybe need to call up my friends in Thailand.
A new research article, conducted with some of the same elephants in the orchestra, shows that they will cooperate on tasks – no surprise to people who are around elephants, but demonstrated very nicely. See:

“From the Cover: Elephants know when they need a helping trunk in a cooperative task”

Plotnik JM, Lair R, Suphachoksahakun W, de Waal FB.
Proc Natl Acad Sci U S A. 2011 Mar 22;108(12):5116-21.

which should be downloadable from the PNAS website.

Tell me if this applies to the “multi-task” question: certainly they perform multiple tasks simultaneously, for instance foraging while being involved in social interactions.

RE brain disorders, I need to find out. I heard of strokes in old elephants, but no first-hand knowledge.
I think it is probable. Elephants are subject to many diseases, including rabies, tetanus, tuberculosis, pneumonia, poisoning from drugs like amphetamine, and most of these have neurological synptoms and some like rabies specifically attack the nervous system. I understand that there is a particularly horrible herpes virus that is very worrying.

And a piece of homework for you: define subconscious in a way that lends itself to observation so that we can answer the question. You may know the “zombie problem”, in which it is very difficult to prove that all other humans except yourself are not robots and have consciousness. See

So hard enough to address for us: maybe we can try to address this question for elephants.

A related question is if they have “REM” sleep, and they are said to twitch and so on during sleep. So my guess is that they likely dream.

Q: Linda Simms

This question is not about elephants, it is about nerves. How long is the longest axion? Do they all come in one size?

A: Dave Sulzer

Wow, Linda very good question. For a single unbranched axon, it would presumably be one from the cortex that travels all the way to the end of the spinal column of the elephant, so perhaps about 12 feet: and then the motor neuron from the neuron it innervates in the spinal cord would go to the bottom of the foot or tip of the tail, so I would guess perhaps 10 feet. This is if the axons were straight, but they aren’t. Moreover, there are sensory neurons running the other direction, so those would presumably also be the longest for unbroken stretches.

However, for the entire length of an axon, including it’s bifurcations, to my knowledge the longest would be the dopamine neurons, as even in a mouse a single neuron can have an axon that has half a meter of length: see the article Matsuda et al in the Journal of Neuroscience last year. This because the axon is incredibly complicated with many branch points, which then have more branch points. We are trying to work on the molecular mechanism of how this occurs, see Schmitz et al 2009 also in J Neuroscience.