male repro

Subject: male repro
From: Peter Woodall <>
Date: Mon, 23 Oct 2000 12:25:37 +1000
At 12:44 23/10/2000 +1000, you wrote:
>As the Monty Python crew used to say... and now for something completely
>different... A friend of mine who's getting into birdwatching, and
>myself, were talking about birds and whether they have penises last
>As you do.
>Anyway... She told me that birds had 'vents', not penises. I told her
>I'd seen two Boobook Owls going for it up the Central Coast years ago
>and that the male definately had a penis!
>I just read at the National Geographic website that only 3% of birds
>have penises and an African species of weaver bird has developed a
>'false penis'. 
>Can anyone tell me any more about this topic? I hope it's not too
>'adult' for anyone.

Hi Lorne

This is a fascinating aspect of biology, I have been interested in reproductive
structure for years and have published papers on mammalian spermatozoa and
testes and
epidiymides and penes.  [No comments from the psychologists on this group,
  I  see no reason not to discuss it on Birding-aus.

To be technical, in veterinary anatomy at least,
the male intromittant organ of a bird is properly called
a phallus, not a penis.  There are several differences: no internal urethra
but an external groove; engorgement by lymph and not by blood; it only 
conveys semen and not urinary products.  If you need more info, a book
"Birds: their structure and function" by AS King and J. McLelland 
is a good source, or other books by Tony King.

In most birds, and the domestic fowl has been best studied, there are two
lateral phallic bodies and a smaller median one.  An erectile papilla at the
end of the vas deferens conveys sperm to the phallic bodies. At mating,
these enlarge
with lymph flow and project slightly from the cloaca, allowing semen to 
flow down a groove into the females cloaca.

In a few groups of birds, the phallic bodies are much larger, forming a
penis-like structure. This is found in the ratites (ostrich, emu, cassowary,
etc, tinamous, and also as a slightly different structure in the ducks and
An ostrich penis is truely large, I examined one at a hunting reserve in 
South Africa and it was about 40 cm long and about 6 cm in diameter.

The african bird you mention in the White-billed Buffalo Weaver,
Bubalornis albirostris found in East Africa. Presumbably similar structures
occur in related sepcies but I don't think anyone has looked, or if they have
they have never published their results.

There is very little comparative work on this topic. I know nothing about the
situation in owls or drongos but a Pheasant Coucal I once examined had long
erectile papillae but apparently normal sized phallic bodies.  One problem
with investigating this area is that the size of the flacid organ may bear
no relation to its size when erect.  While it is possible to get into the
blood vessels and artificially erect a penis, it would be very much harder to
get into the lymphatic vessels of a phallus.  They are much more delicate.


There, I trust that this offends no one, but will it get through Russel's


Dr Peter Woodall                          email = 
Division of Vet Pathology & Anatomy             
School of Veterinary Science.             Phone = +61 7 3365 2300
The University of Queensland              Fax   = +61 7 3365 1355
Brisbane, Qld, Australia 4072             WWW  =
"hamba phezulu" (= "go higher" in isiZulu)


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