Re: Re-emergence of lost features.

["Matthew Troutman" <m_troutman@hotmail.com>]

>
>> Some comparative studies trying to see the intelligence of 
>> some marsupials have shown that many are smarter than your common 
>> eutherians. 
>
>I would like to read these if you have the refs.  My comments came from 
my
>memory of Lillegraven's "Reproduction in Mesozoic Mammals".  He notes 
that
>due to their mode of reproduction placentals
>"thus show greater rates and degrees of cerebralization than
>marsupials...".  While marsupials are wonderfully diverse and skillful 
it
>must be admitted that this brain space must count for something.
>Lillegraven notes the lack of social groupings, social hierarchies, and 
(I
>think) the lack of play among marsupials.
>But then he notes that very little is "known about the relative
>intelligence of marsupials and placentals."

    I have read Lillengraven's paper on that issue and his section on 
marsupial sociality is wrong. Let me list them:

1) Sugar gliders and many phalangeroids including koalas all have very 
structured social groupings. My sugar glider has to have constant 
everyday contact with at least one person for it to be able to survive: 
without family contacts it will die. Same for most marsupials.

2) Many marsupials have very structured social heriarchies. Sugar glider 
groups are dependent on the male for supply of food, protection, and 
shelter. ( I can confirm this because when I bought my sugar glider a 
mate he wanted to be totally dominant and in control; my sugar glider 
not accustomed to that did not fare well, resulting in the mates sale.)

3) Marsupials play very often. Again, sugar gliders ( especially mine ) 
play. My sugar glider goes behind my couch and sneaks up on me, very 
slowly, tempting me to go after her. She loves to jump around all the 
furniture in my houseand back to me. If that's not play, I don't know 
what it is.

>> They also have a higher learning capacity. I happen to own a 
>> pet marsupial, a sugar glider ( _Petaurus breviceps_) and it is not 
only 
>> smart, it is has very acute sensory abilities ( I've seen it jump and 
>> catch things in mid-air in very, very dark areas.) 
>
>I own a male and female Gray Short-tailed opossum.  They are also 
active
>at night.  Their eyes protrude way out of their face.  What sort of
>sensory equipment would be the best aid to locating a phorusrhacoid
>nest--probably olfactory.  I wonder how marsupials rate with this?

     Funny. My sugar glider, as well as having good eyesight, has a good 
sense of smell. It can dig things up in my living room. This is 
generalizing marsupials for no reason other than the notion that they 
are inferior to eutherians.

>> Marsupials are not inferior in their 
>> intelligence, sensory ability...
>
>Then what is the purpose of placentals possessing all those extra 
neurons?

Beats me, I'm no expert.

>>...or reproduction ( the marsupial 
>> reproduction though it produces far less offspring, is very easy on 
the 
>> mother and produces a more stable species community). 
>
>How? Unless it makes a community which moves at a slower pitch.  It 
would
>be easier for a phorusrhacoid to get along in such a community.

Their slower reproduction is the only reason that marsupials have been 
outcompeted by placnetals.


Just all the marsupial intelligence things in:

Sugar Gliders: As Your New Pet

by: Dennis Kelsey-Wood


Regards,

MattTroutman

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