Baby rat or House Mouse?

[thunder]

Originally Posted by beeflysmith

The size of a wood mouse foot may be recorded as max 23mm but the post is comparing a baby rat with a house mouse, the idea that it was a wood mouse (Apodemus sylvaticus) was suggested by another forum user. The nearest I have to a definitive answer is below from a rodent control officer -
"I have looked at your photo and can confirm the rodent is in fact a Mouse.
(A baby rat is a bit like comparing a Puppy from a large dog to a adult
small dog) It's head and feet are disproportionate to its body, and a baby rats tail is much shorter and fatter than an adult mouse"
I would be interested though if your book has the same information regarding foot size for the house mouse (Mus musculus) as this was the initial query.
One last thing which I have been unable to find again this time is the weight of both/either - my wife found a site which indicated that a fully grown house mouse got to a certain weight (for arguments sake I'll say 25gm max) whereas a baby rat, by the time it was independent of it's parents weighed in at a much heavier weight (again, not exactly sure but say 35gm) and it was on this basis my wife decided it had to be a house mouse - that was an earlier capture a couple of years ago, I didn't weigh this little critter but if I capture another I will.

House Mice are smaller than Wood Mice - maximum length of hind foot is 19mm. House Mice are also duller grey brown and not white underneath, just pale grey brown.

Your photograph shows,to my mind, the disproportionate size of the head and feet that your PCO mentions.

Wood Mice that I have seen have much more slender tails, and are more brightly coloured with finer fur than in your picture.

I'll stick to my first opinion - this is a young Brown Rat.

Body weight of

Adult Wood Mice 12 - 27g
Weaned Brown Rat c 40g
Adult House Mice 12 - 22g


henrya

[connerlake]

brown rat or otherwise its a pity, it looked quit healthy.

[Dogghound]

Yep 100% brown rat.

[The Woodman]

Maybe it's time to wind my neck in, once again.

Two images of a similar beast I prepared earlier (two days ago)





Having had it in the hand, measured it, fondled it and realising how alike it is to the OP's images, I am now revising my view and am happy to go along with the Elders opinion as a juvenile Brown Rat.

[Loz]

At uni I did a project involving live-trapping wood mice and spent a lot of time with them - in my opinion the legs on this beast just look too big and chunky to be a wood mouse, so unfortunately I'd have to say rat too.

Loz

[Dogghound]

Yes woodman, yours is a Juv. brown rat too. Nice photo.

[The Woodman]

Thanks Dogghound - I was exactly wrong again!

[richnfamous]

I reckon it's a young rat. It's got a fatter tail and heavier legs.

[beeflysmith]

Hi, firstly thanks to all the people who responded, secondly, I still need help!
I have now caught 8 rodents, and one that got away! My problem is still uncertainty. I have always suspected it to be baby rats, my wife thinks mice. Her reasoning was weight related, the quoted figure for weaned rats was 40gm and none of our little 'friends' were that heavy. So I have weighed the recent catches. One (not photographed - one of his siblings had eaten part of his face overnight - yummy!) weighed 30gm. I now attach another photo of two more recently caught. The slightly larger one at the bottom of the photo just looks like a rat to me. It, like the slightly eaten one also weighed 30gm. The top one weighed 20gm! So is it possible we have both rats and mice using the same route into our kitchen (from the void between the ceiling and the floor above, down some boxed-in pipe work) are they the same species, and if rats, very low body weight weaned rats or in the case of two of them, the 30gm ones, heavy mice?

[Dogghound]

Both brown rats.