I used nail varnish to paint the toe nails of small mammals. I got the best results when using fast drying ones with glitter inside.

But if you want to recognise the animals after more than 3 days I would prefer fur clipping!

I have marked mice with  felt-tipped pen on the tail

My facility used to use cattle dye, but veterinarians had some concern about that.  I believe they now use something like Lady Clairol.

My PhD students used hair dye (oh, they were ladies both). It works.. And stay longer than you need. Just you need to keep animal in the hand for some time, for dye to grip, before releasing. 

I do not recommend hair dye, I got it once in my eyes and was badly sick for two days!

I can only feel very sad for those rabbits they coloured. 

If you cut pieces of hear, you can combine 8 places (the 9th on the head) of the mice and combine this marks, The underfur is mosttimes dark, so it is realy easy to make a lot of combinations. Not toxic and you only need a small scissors. Real easy!

You can also use aluminium earclips, but I don't prefer that (bloody...)

which "wild mice and voles"?

p.s. I mean... their Latin names

We have used ladies hair-dye with small to medium sized mammals here in the tropics of the Yucatan Penninsula with some success. With dark-haired animals we used "Marylin blond" while with pale haired individuals we used "Salma´s black" (names are real!, I just cannot remember the brand). You can also use some peroxide past with some dark haired animals as well. Long haired animals such as possums (Didelphidae) need to be trimmed off before dyeing and the hair can grow fast, so expect not very reliable identification of those if the recapture is quite a long time after the capture/dyeing. Here a picture of a Grey fox (Urocyon cineroargenteus) captured that was marked-dyed in the field and then released back into the wild safe and sound. Good luck!

We use Wella (Wella UK Ltd. Surrey UK) blonde hair-dye to mark our habituated wild dwarf mongooses (see Kern & Radford 2013). We add the marks with an elongated paintbrush while they are foraging near the weighing scale. The marks last for a few weeks to months depending on the time of year and moulting.

Kern, J.M. & Radford, A.N. (2013) Call of duty? Variation in use of the watchman’s song by sentinel dwarf mongooses (Helogale parvula). Animal Behaviour 85: 967–975.

Article Call of duty? Variation in use of the watchman's song by sen...

I once looked for non-toxic hair-dye, and in many publications Nyanzol D is used. I found a company in the USA where they sell this, but there weren't allowed to ship it in the air to Europe due to its hazardous contents. There is also a question on RG about this where another product is mentioned: https://www.researchgate.net/post/Where_can_I_buy_Nyanzol_dye.

You can also use sheep marking crayons 

I used nail varnish to paint the toe nails of small mammals. I got the best results when using fast drying ones with glitter inside.

But if you want to recognise the animals after more than 3 days I would prefer fur clipping!

Great! Thanks for all the suggestions - I'll do a trial with a couple of different methods and see which would be best. Zsolt, they are field voles (Microtus agrestis) and wood mice (Apodemus sylvaticus).

Use of organic hair dye is always recommended. In India there are a few brands, hope you will find organic products (without ammonia specifically) in your country as well. You may use a paint brush and draw tag marks (IIII) like this to identify the recaptures and first tag for captures. Use black color as it stays longer and is identifiable even in dirt or mud.

Hi Sarah,

You can use commercial ear tag for small mammals.

I think Paulo is right; ear tag should be your best option. Hair dye could increase depredation of the marked animals.

Hi Sarah,

I've used L'Oreal hair dye before on small mammals.  We used the permanent variety with the color black, but had several issues with properly identifying the markings of recaptured individuals in the field.  Luckily, we were also using ear tags, which became our primary method of identification.

Hi, we have used Polycolor Brillance Black in a burrowing mammal, the ground squirrel. Our work was first criticised as it may enhance predation in that day-active animal but actually we did not lost a single individual. You may establish different combinations using the internal sides of the whitish leg fur of your species to make individual marks. Allow five mins to fix and just release them. As it vanishes anaturally in cca. two weeks it is not necessary to recapture them to remove the paint - also necessary with more permanent marks. 

https://www.researchgate.net/publication/250068188_Modified_ambient_temperature_perception_affects_daily_activity_patterns_in_the_European_ground_squirrel_(Spermophilus_citellus)

Article Modified ambient temperature perception affects daily activi...

Hello, I have used non-toxic flowers spray paint to mark small indian mongoose for capture/recapture studies. You can use as well vegetable color for cakes. You can use McCormick vegetable color lightly diluted. I have used as well non-toxic Crayola paints for kids used for Easter eggs and other projects.

Hi!! I used and tested it for sea lions, the best brand was framessi, Tonaleg and Issue. In sea lions this kind ok mark last around one year max.

Here is link to the the paper http://travesiasdelobos.blogspot.it/2013/12/tecnica-de-marcado-por-decoloracion-de.html if you have any doubt or question because the spanish or something else be free to contac me!

good luck

Gisela

how long between trapping periods are you thinking? for long studies dye or hair clipping might not be enough. On a long term study I was involved we had the problem of deciding how to mark them. options were: ear tags, toe clipping or  tattooing. we decided to tattoo the toes and it worked perfectly... just needed to perfect our tattooing. another option is chips but those are more expensive.

At ESA last week there was a stand of P-chip. it's so small that you won't even believe it... how it works on the field I can't say but it's an alternative. Off course one also has to consider cost. but wanted to mention it as it looked really cool.

I've used a combination of diluted Hydrogen Peroxide and bleach in a spray bottle to bleach hair on canids. It will lighten very dark hair, but stops short of actually bleaching, in my experience. Depending on the hair color of your voles and mice, I think it would be easier to paint dark marks than to lighten hair color. Good luck.

Use Nyazol fur dye.  Check out John Hoagland's (University of Maryland) research on Prairie dogs using this dye.

An easy and inexpensive option is the use of a black permanent marker.  I have used such markers for marking fox squirrels for a short-term mark-resight study.  

That one definitely will be a good solution, thank you

I know people that have use colours for other reasons ( to know sibbling relationahip and mother to offspring links, but for general marking purposes I would go to ear tags. The student will have to handle the animals anyway, but probably shorter with ear tags, as there is no reason to wait drying of bleaching or colouring products + cleaning the fur area afterwards. Ear tags would made both vole's and student's lifes easier. Maybe fur cutting is also good but  then there may be problems with posterior  locations of the cuts and so on, while a couple of ear tags have an unic and hard to mis read number id.

good luck to the student (and to the voles :) )

Fer

I agree with Fernando. CMR analysis requires the individual recognition of marked animals. This requirement is not securely met, even over short periods, with fur dying, fur clipping, food dying, or even with toe-clipping (which anyway I disapprove for ethical and physiological reasons). Ear tagging is the most secure. But tag both ears! Losses typically occur shortly after tagging because the tag was not properly placed…

I join a publication on Michel ear tags, an excellent alternative to the more classical Fingerling fish tags.

Good luck,

Éric

Article A new ear‐tag for small mammals

 Following my answer about marking small mammals, three persons requested the full text of my paper entitled A new ear-tag for small mammals (1986, J. of Zoology 209, 302-304). Not being familiar with RG, I don't know whether they received it. In case of problem, please contact me directly at [email protected]. Best regards.

Your download link (above) worked fine. Thank you Eric for this interesting paper.

I used agricultural dye to mark Antechinus (about the size of a mouse) and bush rats. The dye came off the fur but remained on the skin for a short period. It didn't work for individual identification and was only useful to count the number of individuals present in a 5 x 6 trap grid.

OK. Good luck.