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ANUROGNATHIDS & VAMPIRISM
David Peters wrote...
On "Walking With Dinosaurs" the narrator says that
anurognathids spent their entire lives snapping up the
insects attracted to sauropod hide. Is this hypothesis in the
literature? And if so, what is the reference?
Obviously Martill and I chased this up for the _Walking
With Dinosaurs: The Evidence_ book we did (we may or
may not mention it.. can't remember). Tim Haines came up
with the idea based on the obvious analogy with oxpeckers
(_Buphagus_): there's nothing more to it than that AFAIK.
Firstly, oxpeckers are reported to have particularly recurved
claws and other hindlimb features that assist in clinging to
ungulate hides: this is often asserted but I don't know of any
functional study that 'demonstrates' it. While oxpeckers do
keep down the numbers of ticks present on large ungulates
according to some studies (most notably Stutterheim et al.
1988: as a consequence they've been deliberately introduced
to areas [e.g. Shamwari Game Reserve] with tick problems),
they don't just eat parasites and biting insects - they eat a lot
of snot, dead skin, blood and earwax (in fact one study
showed that Cape buffalo deprived of oxpecker attention
soon had ears so full of wax that their hearing was
In fact some authors have argued that blood is the preferred
food of oxpeckers (Bezuidenhout and Stutterheim 1980,
Weeks 1999) which makes it unlikely that they are
beneficial to their hosts and raises the possibility that they
are on their way to specialised vampirism (which obviously
is documented elsewhere in passerines: _Geospiza
difficilis_). Most recently Weeks (2000) has proposed that
mammal-oxpecker interactions are more complex than most
authors have thought and that oxpeckers may be parasitic on
some animals (on hippos they apparently only feed on
wounds), commensal on others and mutualistic on others.
Bezuidenhout, J. D. & Stutterheim, C. J. 1980. A critical
evaluation of the role played by the red-billed oxpecker
_Buphagus erythrorhynchus_ in the biological control of
ticks. _Onderstepoort Journal of Veterinary Research_ 47,
Stutterheim, I. M., Bezuidenhout, J. D. & Elliott, E. G. R.
1988. Comparative feeding behaviour and food preferences
of oxpeckers (_Buphagus erythrorhynchus_ and _B.
africanus_) in captivity. _Onderstepoort Journal of
Veterinary Research_ 55, 173-179.
Weeks, P. 1999. Interactions between red-billed oxpeckers,
_Buphagus erythrorhynchus_, and domestic cattle, _Bos
taurus_, in Zimbabwe. _Animal Behaviour_ 58, 1253-1259.
Weeks, P. 2000. Red-billed oxpeckers: vampires or
tickbirds? _Behavioural Ecology_ 11, 154-160.
See the following for a good reference list on oxpeckers...
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL
tel: 023 92846045