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emu encounters

Emus roam free on the grounds at our local zoo (in Canberra), much as peacocks do at zoos in other countries. I was checking out an emu's feet from very close-up last weekend, getting reference for how to paint a T. rex foot.

Although the zoo inhabitants are very tame, I was menaced by an emu in the wild several years ago. I was peeling a banana when an extremely tall bird approached me, obviously wanting the fruit. I tried to hide it behind my back, but it then seemed ready to attack. So I quickly gave it the banana which it gulped down in one go. I'm 6 foot 2" and this bird towered over me. Luckily it walked back to its 'flock' after it was sated. I've never heard of anyone being killed or even injured by an emu, but I hadn't realised how obstreperous they could be until this incident.

I've been mobbed by kangaroos as well, but I guess that's too off-topic!

Peter Markmann

On Wednesday, January 14, 2004, at 03:57  PM, Nancy Cavanaugh wrote:

I am interested in anything I can learn about the bird. Here in the US there
doesn't seem to be a lot of information about them, even though there has been
a growing population of emu ranches and interest in the various products
created from the emus.

Hmmm... that's interesting. Nothing I've read to date (and I've only been
researching this for a couple of months, and 98% of that research has been done
online as books about emus, at least in the public sector, in the US are rare
to non-existent) said anything about the emu being from a common ancestor with
the cassowaries. Who was the common ancestor? How did they evolve differently?

I had read in several places that it is believed that the emu has evolved very
little from its earliest form. One would assume, based on that information and
what you've said, that the cassowaries probably evolved very little from their
earliest form. Has that been the case?

One specialist I spoke to suggested that I say that it is believed that the
emus date back 80 million years ago but that there is more recent research that
suggests they may only be 45 million years old. Your suggestion is basically
the same so I think I will take that cue unless there is a further dispute
about it.

Sorry for the typo on Mr. Cracraft's name. The erroneous spelling is from a few
websites where I found the information about when the dating of the emu
happened. When did Mr. Cracraft announce his findings for the dating of the
emu? Was it '71 or '73?

You forgot about the extinct Tasmanian Emu which is supposed to be a sub-
species of the "mainland" emu. =) Did they ever live on the mainlanda? How did
they get to Tasmania?

Nancy Cavanaugh <who is sure she has a lot more questions but is falling asleep
at the computer and needs to go to bed to hopefully not be sick tomorrow>

PS, I am sorry if some of my message is confusing. I am getting sick (hopefully
not the flu!) so my thought processes are not working right.

-----Original Message-----
From: Ronald Orenstein <ornstn@rogers.com>

Of course there is no certain way to determine exactly when the modern emu,
Dromaius novaehollandiae, first "appeared on earth" -- and, since it
obviously evolved from an ancestor which was not quite identical to it, it
is not even correct to say that it appeared (as opposed to achieving a
certain level of differentiation from its ancestors). So the first
question to ask is, are you interested in when the modern species arose,
when the genus arose, the family, or the order?

There are three ways of getting some sort of answer to these questions: the
obvious one, of course, is to come up with a fossil of known age. Another
is to use genetic data to estimate how long ago a species (or higher
category) diverged from the common ancestor it shared with its nearest
living relative (in this case, with the cassowaries if you are referring to
the emu family, as opposed to the living species -- bear in mind that there
are two recently extinct emu species, from King Island and Kangaroo
Island.) A third, perhaps more questionable, technique is to look at the
history of continental drift. The argument would go, for example, that the
emu lineage -- or at least the emu-cassowary lineage as separate from the
lineage is that lead to other large flightless birds such as ostriches --
must be at least as old as the point at which Australia broke away from the
land mass of Gondwanaland. That is where the 45 million-year-old figure
comes from, because that is apparently the time at which Australia and
Antarctica separated. However, this does not tell us when emus and
cassowaries differentiated from each other, as they both occur in
Australia. Presumably this happened later, but not necessarily as the
separation could have occurred before the birds became isolated on the
Australian landmass. Obviously there are none left in Antarctica!

That said, and noting that Joel's name is "Cracraft", the Handbook of the
Birds of the World, Volume one, published in the 1992, notes that the
oldest fossils that can be ascribed to the living genus of emus are only
some 5000 to 10,000 years old, and belong to the King Island Emu which has
since become extinct. Obviously, emus as a lineage are older than
that. however, the most recent book I have on the subject, a detailed
monograph called "Ratites and Tinamous" by SJJF Davies (Oxford, 2002),
casts doubt on any of the attempts to determine precisely how old these
groups of birds are, and does not suggest a date.

I would be inclined, given this, not to attempt to come up with an age for
the emu family. All that I think you can really say is that emus and their
closest relatives, the cassowaries, have been separated from their nearest
relatives ever since Australia drifted away from Antarctica and so,
together, must have been around in one form or another for at least 40 to
45 million years.

Ronald I. Orenstein Phone: (905) 820-7886
International Wildlife Coalition Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2 mailto:ornstn@rogers.com