Rhodamine B is a perspective biomarker for unselective animal marking. Despite several successful attempts in practical use, the method is still under development. The critical problem is mark detection. We offer the new way of rhodamine mark detection which is simple, cheap and effective. White mouse were used as the model object. Instead random hair sampling for fluorescent microscopy we suggest an inspection of all animal body surface. For this aim it is possible to employ a green laser (usual laser pointer) as an illuminator and an orange glass or plastic as a filter before observer`s eyes.

When testing the method it is established that in adult animals fluorescing areas shortly after marking is usually less than half the surface of the body, being reduced over time. The maximum time frame in which the mark in the pelage was detectable during the examination of living mice, ranged from 166 to 423 days. It was revealed that in suckling mice the mark can be formed by milk of mothers who received a dose of Rhodamine B. In these cases the fluorescence manifests itself in all or most part of the body surface. The mark is maintained in the fur of mouse cubs at least four months.