ALAT Animal Identification Techniques

Question 1

Which permanent identification method involves creating a unique pattern of holes or cuts in a rodent's ear?

Accepted Answer

Ear notching or punching

Answer

Ear notching or punching creates a pattern of holes/notches that uniquely identifies individual animals or litters. It is one of the most common permanent ID methods for laboratory rodents and can encode numbers using position on left vs. right ear.

Question 2

What is the most reliable method for sexing neonatal mice when external genitalia are not yet differentiated?

Accepted Answer

Anogenital distance

Answer

Anogenital distance (the space between the anus and the genital papilla) is the most reliable indicator in neonates: males have approximately twice the anogenital distance of females. Nipples and coat color are not reliable sex indicators in newborn mice.

Question 3

Which identification technology uses a radio-frequency device implanted subcutaneously that emits a unique number when scanned?

Accepted Answer

Transponder (microchip)

Answer

A transponder (microchip) is a radio-frequency identification (RFID) device implanted under the skin. It is read electronically by a handheld scanner, provides permanent non-visible identification, and does not alter the animal's external appearance.

Question 4

In the standard AALAS mouse ear-notch numbering system, notch positions in the RIGHT ear represent which values?

Accepted Answer

Single digits (1, 2, 4, 8)

Answer

In the standard system, right-ear notch positions represent single-digit values (1, 2, 4, 8) and left-ear positions represent tens (10, 20, 40, 80). Combining positions allows identification of individuals up to number 159.

Question 5

Which of the following is a TEMPORARY animal identification method?

Accepted Answer

Fur clipping or marking

Answer

Fur clipping or marking with non-toxic dye is temporary because fur regrows, eliminating the mark. Permanent methods include ear tattooing, ear notching, and microchip implantation. Temporary marks are only appropriate for short-term studies.

ALAT - Assistant Laboratory Animal Technician Practice Test

ALAT - Assistant Laboratory Animal Technician Practice Test

ALAT Animal Identification Techniques