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Re: Alvarezsaur spurs (was Re: dino-lice)



Augusto Haro <augustoharo@gmail.com> wrote:

> True, the aardwolf is truly strange. It is truly cursorial being
> mostly a myrmecophage, so the questioning of myrmecophagous habits
> because of being cursorial seems to lose a limb.


Not entirely.  The aardwolf is fairly inactive in the African winter,
and spends most of the time huddled inside its subterranean burrow.
Harvester termites (its preferred food source) remain holed up in
their mounds during the winter; and although the aardwolf can feed on
other items, the winter period is nutritionally (and hence
energetically) stressful for the animal - hence the reduced activity
levels.  The other large myrmecophagous mammal that it shares its
habitat with, the aardvark, continues to feed by excavating hard
termite mounds (including those of the harvester termite) that are
inaccessible to the aardwolf.


The aardwolf lacks the predatory ability to be able to hunt and
survive off large numbers of small vertebrate prey during the winter.
Nor does it subsist on carrion.  Despite its crappy digging abilities
(especially compared to the aardvark), the aardwolf is regarded as a
termite specialist.


> Other thing: how does it acess to the contents of termiteria?


It doesn't.  The digging abilities of the aardwolf are fairly limited.
 It rarely even digs its own burrow, but steals those of other mammals
(e.g., aardvark, porcupines).


There's evidence that the aardwolf is a recent convert to
myrmecophagy.  According to one molecular analysis (Koepfli et al.,
2006), _Proteles_ diverged from the (other) Hyaenidae only about 10.6
million years ago (although morphological analyses tend to favor a
date around twice that).


My aardwolf analogy for alvarezsaurs only goes as far as demonstrating
how a myrmecophage can (and do) eat other food items, and how an
insect-eating lineage can evolve from carnivores.  In most respects
(termites as the major food source; reliance on exposed termites at
ground-level; low activity levels in winter; living in subterranean
burrows) the lifestyle of the aardwolf is nothing like what I would
envision for alvarezsaurs.  I see alvarezsaurs as fast bipeds that
were active all year round, and were only opportunistically
myrmecophagous.




Cheers

Tim