RE: Arboreals dinos, handedness, what people sez etc.

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Jerzy Dyczkowski wrote:

>Flight in bats probably evolved by jumping up or hopping down the rocks
>catching insects with front paws (modern bats use wing membrane to catch
>insects).

I too would like to see a precise reference for this hypothesis.

>In modern ecosystems, there is well developed group of bigger arboreal
>animals. This includes herbivorous and frugivorous primates, squirrels
>and some procyonids, bears, marsupials and hyraxes; and predatory
>marsupials, cats, martens and viverrids.

By spending most of their time in inland forests, prehistoric animals
(whether bird, mammal, or reptile) are setting the odds against them when it
comes to the chances of being fossilized.  Notice how the Mesozoic avian
record seems to be biased toward littoral species.  Maybe there were
kinkajou or koala-sized mammals living in the trees of the Mesozoic - and we
just haven't found 'em yet.

>Hopping down the trees from nest is not usual in modern birds, who
>generaly leave the nest as inconspiciously as possible.

But... in the absence of Pizza Delivery, somebody has to leave the tree to
find food for the chicks.  :-)

>"Handedness" can be seen in elephants and mammoths, because one tusk is
>always more worn. Something similar might probably be seen in dinosaur
>horns or claws. 

Not if theropods hands were *designed* to clasp objects by using both hands
at the same time.



Tim