# Rat ID help



## shell477 (Nov 26, 2013)

Is anyone able to confidently ID this as to whether it is a native rat or a 'pest' rat? 

Have received a nest of three of them. Found in south-western Victoria. Nest was made of leaf litter, grass, plastic rubbish and twine, dug up from under a concrete slab (shed on top) on a farming property but there is plenty of native brush nearby. 

Asking here because I thought rat breeders might have some ideas...


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## adderboy (Nov 26, 2013)

I'm not an authority on rats, but one of the more conclusive ways of telling natives apart from introduced is the nipple count. None of your shots show the ventral side - do you have any? It would make ID easier.


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## shell477 (Nov 26, 2013)

thankyou adderboy, i do not have one sorry. i am about to go out, so i will get one at their 3pm feed and post it up then.


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## brown.snake (Nov 26, 2013)

Brown rats (Rattus norvegicus),the wild ancestor of the domestic rat will make good pets if you hand raise them i have had black and brown rats as pets when i was a kid


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## shell477 (Nov 26, 2013)

The plan is to release them once they are grown 

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## mummabear (Nov 26, 2013)

Can you fill me in on the count? 



adderboy said:


> I'm not an authority on rats, but one of the more conclusive ways of telling natives apart from introduced is the nipple count. None of your shots show the ventral side - do you have any? It would make ID easier.


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## Wild~Touch (Nov 26, 2013)

Native rats usually have small litters 

Pest rats have huge litters


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## Bluetongue1 (Nov 26, 2013)

Nipples aside, it looks to be the native Bush Rat (_Rattus fucipes_). The Swamp Rat (_R. lutreolus_) has quite dark grey feet and the eyes do not protrude at all, as they slightly in _R. fuscipes_. Both these species can be distinguish from the introduced Black Rat by the tail length. In _R. fuscipes_ the tail is just short of the head and body length and is about two-thirds in _R.lutreolus_, while in _R. rattus_ it is longer (only about one fifth). Bear in mind that head-body length is measured from the snout tip with the head forward and the body completely flattened and not crouching. An added difficulty is the tails are still growing on young of their age. 

As Adderboy said, the number of teats is a good indicator. However, they can in fact vary within some species and so may not be diagnostic on their own.

Blue


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## GBWhite (Nov 26, 2013)

Could be either but really the little critter is too young to make a positive id. You'll have to wait a little longer to confirm what it is. As well as having more nipples the tail length of adult (R fucipes) is distinctly shorter than their body, R rattus have tails as long or longer. R fucipes also have short rounded ears compared to the long pointed ones of the old R rattus.
Nest materials are no real indication either, but from what you've described and considering native rats usually construct nest of natural material it just might be R rattus. Just my opinion.

One thing about Bush Rats (R fucipes) is that they are very shy creatures and are reluctant to go into or under buildings and as a rule are found far away from human habitation.

George.


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## shell477 (Nov 26, 2013)

Not the best photo sorry - I had a close look at the little girl and to my inexperienced eye, I can count 5 pairs of nipples (I think). One pair just above arms, one just under armpit, one below that, then a big gap then 2 pairs towards the bottom legs. 





Ooh i think I just spotted a sixth one below that last one??


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## Bluetongue1 (Nov 26, 2013)

I should not have presumed and should have asked for more details of the location. It could also possibly be a wild Brown Rat and I cannot totally exclude a Pseudomys species. 

As George said, R. fuscupes are found in areas of dense undergrowth, often with ferns and fallen logs.

Most of the terrestrial Australian mammal fauna has been around for around 100 million years. Rodents, probably a mouse-like ancestor, are a ‘late arrival’ at around 15 million years ago and have since evolved to into everything from water-rats to hopping mice. In all of these species, the females have only 4 nipples and all are located in the lower abdominal or inguinal (groin) areas. These rodents are referred to as the “old endemics”. 

There are seven species of native rodents all belonging to the genus _Rattus_. These appear to have been derived from a common ancestor that arrived millions of years later than the original founding rodent stock. These seven species may have anywhere between 6 and 12 nipples, 6 of which are always located on the lower abdomen and the rest, if present, in the pectoral area. These rodents are referred to as the “new endemics”. 

The Long–haired, Dusky and Cane-field Rats have 12 nipples. Bush, Swamp and Pale-field rat have 8 or 10 nipples. The Cape York Rat has 6 nipples. The Bush Rat subspecies “lutreolus” in SW Vic (sometimes split into two subspecies) has 10 nipples.
Black Rats usually have 10 nipples, Brown Rats 12.

Blue


UPDATE: Indeed I was too presumptuous. Well done Brown.snake – right on the money. 
Just goes to show that there is no substitute for experience.


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## brown.snake (Nov 26, 2013)

one of my nicknames at school was Willard :lol:


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## shell477 (Nov 26, 2013)

Thanks everyone. Guess I will have to wait a week or so and see how they grow

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