Rattus or Mastacomys sp. (genus)

An unidentified rat species at Rendezvous Creek, ACT

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Identification history

Rattus or Mastacomys sp. (genus)	5 Jun 2020	MichaelMulvaney
Rattus fuscipes	5 Jun 2020	dhkmapr
Unidentified	5 Jun 2020	ChrisHolder

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4 comments

DonFletcher wrote:

5 Jun 2020

Rattus, but is it R rattus or R fuscipes? I cant tell but the tail length makes me lean toward R rattus.

dhkmapr wrote:

6 Jun 2020

I'm finding it difficult to judge tail length from the photos. One interpretation of the first photo is of a short tail, but with features of the rock behind it suggesting it is longer. The second photo suggests a short tail, but this could be due to perspective. If we're satisfied that the tail is long, and noting that the muzzle is pointed, not rounded, then R rattus is a good ID.

DonFletcher wrote:

6 Jun 2020

Hi dhkmapr, they seem never to line themselves up with a ruler and the diagonal perspective reduces confidence in the estimate. The actual requirement is to bend the tail forward past the nose so we are doing a lot of work with out imagination to judge from photos. One day someone will do a test with trapping + cameras and find out how good we are at identifying known examples of these two species.

dhkmapr wrote:

6 Jun 2020

Don. I agree. Variation in camera resolution adds another degree of difficulty. ... not to mention spp that are hard to separate even in the hand - eg some sympatric populations of A stuartii and A agilis.

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