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Re: To climb or not to climb

-----Original Message-----
From: Jaime A. Headden <qilongia@yahoo.com>
Date: 18. december 1998 9:25
Subject: Re: To climb or not to climb

>  You know, this gets me thinking about the Hateg, the "dwarf"
>locality in Romania, and how the plants there may have contributed to
>the smaller animals, or developed _brachium in brachium_? Perhaps
>Berislav can enlighten me.

The causes of parallel dwarfism of otherwise big herbivores are various:
first of all, constant limited or reduced  food resources (either because of
a limited area - island ; either through slower plant bio-mass regeneration;
or most probably both); sustaining a viable number of individuals of the
species (for reproduction)- "lebensraum"; absence of big predators.
The consequences of the above factors lead to dwarfism of big herbivores and
gigantism of some smaller animals (dwarf elephants, giant hedgehogs and rats
in the Tertiary, also a lost of capability to fly  in some birds). It is my
guess that the process of evolving into bottom line dwarfs was quite fast in
geological terms. I wonder if bigger (older) elephant fossils (Mediterranean
or Vrangel's islands) were found in the same area as the dwarf ones were
found - to determine the rate of reaching diminutive.
Efficient browses can devastate a limited area. They can also prevent
bigger plants like trees to develop full size by constantly clipping off its
shoots ("bonsai syndrome"). It is a possibility, that the islands inhabited
with pigmy dinosaurs had dwarf trees ( a close circle).

Berislav Krzic