As stated in the Guide for the Care and Use of Laboratory Animals (the Guide, p. 75):
"As a method of identification of small rodents, toe-clipping should be used only when no other individual identification method is feasible."
Amputating the toes of rodents as a means of identification must not be practiced without explicit approval of the ARC upon presentation of scientific justification in a submitted protocol. Such use of toe clipping will only be considered for altricial (no hair) neonates less than seven (7) days of age. When there is a research need to identify animals before ear notching or ear tags are feasible, marking the external skin with an indelible marker or administering a "tattoo" with a small injection of dye are effective methods that do not involve mutilation. Small transponder or RFID "chips" are also available for subcutaneous implantation into rodents.
Approved 10/28/02; Revised 7/26/04, 4/16/10, 4/10/23; Updated 1/18/11; Reviewed 3/14/16