New Zealand's biggest rat?

Discuss natural history subjects not strictly related to birds. Reports of interesting mammal, reptile, and invertebrate sightings are welcome.
Colin Miskelly
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New Zealand's biggest rat?

Postby Colin Miskelly » Sat Feb 19, 2011 5:38 pm

This morning I trapped the largest rat I have ever seen - a 550 g male Norway rat caught alongside our compost bin in central Wellington.

Norway rats are the largest of the three rat species in New Zealand. According to The Handbook of New Zealand Mammals (2nd edn), truly wild Norway rats can get up to 422 g (Mokoia Island female), while for individuals from commensal populations (those living alongside humans) "weights exceeding 500 g, and exceptionally 600 g, have been reported in Britain. The largest of three commensal females caught near Christchurch weighed 364 g".

I would be interested to hear of any larger individuals (and also to obtain any such specimens for the Te Papa collection).

Colin Miskelly
Curator Terrestrial Vertebrates
Museum of New Zealand Te Papa Tongarewa
Ian Southey
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Re: New Zealand's biggest rat?

Postby Ian Southey » Wed Feb 23, 2011 9:35 am

Colin

There is a truly massive rat on display in reception at DOC Warkworth but I forget the details. Probably worth checking up on.

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tim
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Re: New Zealand's biggest rat?

Postby tim » Wed Feb 23, 2011 4:36 pm

I heard about that Rat too Ian from a Doc Ranger on Tiri, that was found on one of the islands in the Gulf and costed around $100,000 to catch but by the time they caught it the rat was one fat rat so they displayed it and called it the $100,000 dollar rat or somthing like that.
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Steps
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Re: New Zealand's biggest rat?

Postby Steps » Thu Feb 24, 2011 8:22 am

There is a lot more to that story than DoC lets on...rather an embasiament actually...a sloppy research project that went wrong....I actually saw that rat in its cage just before the release....The is a hell of a lot of stuff in DoC that never sees the light of day.....other depts it does....unless a platform falls down it never comes to light.
It was 'supposidally ' the rat swimming great distance between islands and caused a major stir in the press around the world.
I did not hear of the part about the $1m rat being over weight thu.

I worked around the freezers on Kings wharf many decades ago....those rats may not have been heavy, I dont know , but big?...coats like purssian cats.
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Neil Fitzgerald
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Re: New Zealand's biggest rat?

Postby Neil Fitzgerald » Thu Feb 24, 2011 10:28 am

If this is James Russell's rat (I'll enquire) it would be a bit unfair to call it failed research or a cover up, considering the number of publications that came from it, including in Nature, Wildlife Research, and even a childrens book (which I'm admit I haven't read).
The star rat of that work (M1) took 85 days to be caught, after it swam (>400 m) to another Island. Another (M3) took 49 days to find (killed by poison) during which time it gained a lot of weight (33%) and ended up at 441 g.
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Neil Fitzgerald
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Re: New Zealand's biggest rat?

Postby Neil Fitzgerald » Thu Feb 24, 2011 4:39 pm

The Warkworth rat was apparently caught in 2008 on Motuora Is. 400 traps were set after some children found tracks on a beach, and over $10,000 spent catching it.
Over 25km from Russell's study.
Rob Chappell
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Re: New Zealand's biggest rat?

Postby Rob Chappell » Mon Mar 25, 2019 8:11 pm

Hi Colin

Thats a reasonable rodent but not as large as the one i caught Xmas 2016 on Ohinau island - a Norway weighing in a 605 grams, this was the largest Rat that James Russel had ever come across. We have it stuffed in the DoC Office at whitianga for all to see.

cheers

Rob
Colin Miskelly
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Re: New Zealand's biggest rat?

Postby Colin Miskelly » Mon Mar 25, 2019 9:09 pm

Hi Rob

Glad you found this old thread and provided an update. I hadn't heard about the Ohinau Norway rat incursion - hope it was only this one animal. No wonder it was so fat, with an entire island of kai:

https://blog.tepapa.govt.nz/2014/02/13/critters-of-ohinau-island/

https://blog.tepapa.govt.nz/2014/02/10/seabirds-of-ohinau-island/

Cheers
Colin

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