A question about rats

To: "Steve Holliday" <>, <>
Subject: A question about rats
From: Bron King <>
Date: Sun, 11 Mar 2007 16:59:05 +1100
I am not aware of any confirmed breeding records for R. norvegicus in Canberra.  Although individuals turn up from time-to-time in interstate furniture and produce trucks, etc, it seems that they are not established far from the coastal strip around major cities - except for a population along the middle reaches of the Murray River.  They also seem to have declined over the past century or so.  This may be due in part to competition from the more successful R. rattus

All R.rattus that I have trapped in Belconnen in recent years have been similarly coloured to yours, and 19cm is the median head-body size for R.rattus.  But the tail-length is interesting.  Median tail-length of R. norvegicus is 16% shorter than median head-body, while for R. rattus, it is 20% longer.  Pity we don't know how much went to the dog.

Daryl King

 At 03:50 PM 11/03/2007, Steve Holliday wrote:
Apologies for the mammal question but does anyone know whether Brown Rats (Rattus norvegicus) occur in Canberra, I haven't been able to find out either from the net or books. I found a rat that next door's dog had killed (during one of his regular escapes) on our back lawn this morning. At first I assumed Black Rat, which we see here every now and then, but this looked a bit larger and stockier, with a thicker tail. Unfortunately it was so badly chewed that I couldn't determine ear length (which is a good way to separate the two spp), one ear was gone altogether, and only a bit of the other was left. Head-body length was about 19cm, with the tail slightly shorter, although at least part of it was missing. Colour of the upperparts was grey-brown with some longer black guard hairs, underparts were paler. Probably just a large Black Rat, but any suggestions either way welcome!
ps I haven't saved the specimen, it was already fly-blown and not very nice. Guess I could dig it up again if anyone's desperate to see it.
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