IUBio

Dolphin brain

Krakatoa stephan at nospam.ucla.edu
Thu Jan 28 03:19:48 EST 1999


In article <36ae19c5.402246309 at news.udel.edu>, who at cares.com wrote:

> >It's true that dolphins have unilateral sleep. And if I 
> >remember correctly, dolphins also have little or non REM 
> >sleep. 
> 
> Interesting. Do you remember your source, i'd like to dig in a bit.
> 
> 
> The  amount of time spent in REM sleep correlate
> >negatively with neocortical volume.
> 
> The're many correlates with REM (also note intra-individual changes:
> development and aging). 
> I do not understand why thier amount of REM "explains" their cortical
> volume.
> Only if the function is exposed I will agree. But REM doesn't relate
> to function, it refers to a phenomenon.
> 
> 
> mammal with the largest neocortex when the effect of
> >body mass scaling is removed (that is, neocortical volume
> >devided by bodymass^0.65) is the Echidna. The Echidna 
> >(also called the spiny ant-eater) is a monotreme,
> >i.e. one of the most relictual mammals. For example, the
> >it lays eggs and lack mammillary nipples. So the
> >most relictual (primitive) mammal species has the biggest 
> >neocortex. Interestingly, the Echidna lack REM sleep 
> >all together.
> 
> So what? 
> 
> 
> >
> >If I am not wrong, the small amount (none?) of REM sleep
> >found among dolphins fully explain their enlarged
> >neocortex. But the functional role of REM sleep remain 
> >a mystery.  
> 
> 
> So what did you "explain"?
> 
> Thanx ffor the info though!  :  )

Their persistant inability to develop tools to deal with constant threats
from tuna nets, killer whales, and sharks is a testament to their vastly
superior intelligence to humans.



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