Broad-toothed Rat at Charlotte Pass, NSW
Identification history
| Mastacomys fuscus | 16 Mar 2023 | DonFletcher | ||
| Rattus rattus | 14 Mar 2023 | CarbonAI | ||
| Mastacomys fuscus | 14 Mar 2023 | MLH |
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User's notes
Single recently deceased individual in snow gum woodland
10 comments
DonFletcher
wrote:
14 Mar 2023
Hi @BelindaWilson, Hi @ChrisM, Hi @WillO,
This is clearly not Rattus rattus and it is also not Rattus lutreolus but, not being familiar with Mastacomys fuscus, I'm not 100% sure I should rule out Rattus fuscipes. Things that make me like M. fuscus for this are: tail shorter than HB, ears almost covered by cheek hair, and hunched appearance, but there are problems. Three things that argue against ID as M. fuscus are: (i) lack of flecking in the fur, (ii) colour of feet seems more like R. fuscipes (brown with a pinkish tinge) than M. fuscus (dusky brown above and below according to Menkhorst et al), and (iii) tail is not coloured 'uniformly brown only slightly paler below' but is pretty well a classic R. fuscipes tail colour. I'm inclined to go with Mastacomys fuscus, but would appreciate your opinions.
This is clearly not Rattus rattus and it is also not Rattus lutreolus but, not being familiar with Mastacomys fuscus, I'm not 100% sure I should rule out Rattus fuscipes. Things that make me like M. fuscus for this are: tail shorter than HB, ears almost covered by cheek hair, and hunched appearance, but there are problems. Three things that argue against ID as M. fuscus are: (i) lack of flecking in the fur, (ii) colour of feet seems more like R. fuscipes (brown with a pinkish tinge) than M. fuscus (dusky brown above and below according to Menkhorst et al), and (iii) tail is not coloured 'uniformly brown only slightly paler below' but is pretty well a classic R. fuscipes tail colour. I'm inclined to go with Mastacomys fuscus, but would appreciate your opinions.
MLH
wrote:
14 Mar 2023
Note that the habitat is classic M. fuscus - above the snowline and in dense understorey with mix of forbs, grasses and shrubs
DonFletcher
wrote:
14 Mar 2023
Hi MLH, many thanks for these photos. Small mammals are hard to ID from photos. For future reference, the guidelines at the beginning of the section may help, as follows:
Tips to increase the potential for correct identification:
An image that is sharp, not blurry;
A scale;
A view of the whole animal (preferably stretched out if it is a carcass);
Views of every surface - (not always possible but ideally this includes a profile of the head, good views of the ears, the belly, the pads on the hind feet, and a good view of the fur and skin on the tail from below and above);
Views of the teeth; and
A count of the number of teats.
Tips to increase the potential for correct identification:
An image that is sharp, not blurry;
A scale;
A view of the whole animal (preferably stretched out if it is a carcass);
Views of every surface - (not always possible but ideally this includes a profile of the head, good views of the ears, the belly, the pads on the hind feet, and a good view of the fur and skin on the tail from below and above);
Views of the teeth; and
A count of the number of teats.
DonFletcher
wrote:
14 Mar 2023
Hi MLH, in the area, did you see tunnel-like runways in the grass with numerous rat-sized droppings containing grass fragments?
MLH
wrote:
15 Mar 2023
I looked for the tunnels afterwards but didn't see any obvious signs in the area. The immediate vicinity was more shrubby than grasses and thus less likely on cursory glance to contain obvious tunnel like structures. No scats apparent on the entire walk. I snapped the pictures quickly on the return section of the walk and I thought I was probably not capturing the diagnostic features (Like tufts of hair in the ears according to this site https://www.swifft.net.au/cb_pages/sp_broad-toothed_rat.php) In the two hours between walking out and back the maggots got going so I wasn't keen to examine the teeth too closely. Although I had nothing to scale it against it was quite large.... as big as an adult Rattus norvegicus.
DonFletcher
wrote:
15 Mar 2023
Will has referred this on to two other Mastacomys gurus, Linda Broom and Ken Green. We await their verdicts.
BelindaWilson
wrote:
16 Mar 2023
Hi Don and MLH, I have referred the record for Kiarrah Smith and she said: "Definitely not R. rattus, as Don said, though if it were a Rattus, it'd be R. lutreolus. I would lean toward M. fuscus too, though I'm not terribly familiar with the species - from what you can see of the feet and tail (though blurry), it doesn't look like a Rattus."
DonFletcher
wrote:
16 Mar 2023
I just saved these pics to where I can see them on a better computer monitor. Two things i had not considered before were the tail being SLIGHTLY paler below, and the poor view of the foot pads that can be got from the 3rd picture. Together with Kiarrah's comment, its enough for me to confirm Mastacomys. But if Ken Green and Linda Groom disagree we can change it. cheers
Location information
- Maps Kosciuszko National Park
- Places Charlotte Pass, NSW
Sighting information
- 1 Abundance
- MLH Recorded by
-
Collections
NSW Government Priority Species Mammals Rats Rodents MLH Canberra & Southern Tablelands NatureMapr
Additional information
- Unknown Gender
- Breeding behaviour
- Deceased Animal health
Species information
- Mastacomys fuscus Scientific name
- Broad-toothed Rat Common name
- Sensitive
- Endangered *
- Non-invasive or negligible
- Up to 1506.16m Recorded at altitude
- Machine learning
- External link More information
Record quality
- Images or audio
- More than one media file
- Verified by an expert moderator
- Nearby sighting(s) of same species
- GPS evidence of location
- Description
- Additional attributes
