An ear tag 1 for identifying an animal, enables a sample of biological tissue to be taken when the tag is applied to the animal. The tag includes a male part 2 and a female part 3 which are assembled by irreversible interlocking between the male part on one side of the animals ear and the female part on the other side of the ear. The stem 22 of the male part includes a detachable head 23 having a hollow distal part 29 provided with a cutting edge 25 for cutting out a biological sample when the head perforates the ear of the animal. The female part includes a central tube 31 for receiving the head and at least partially receiving the stem when the ear tag is applied, and a detachable sample container 32 arranged in the axial extension of the tube. The proximal end 35 of the container has a first opening 33 for receiving the head 23 of the stem when the ear tag is applied, and the distal end 36 of the container has a second open end 34 enabling the inside of the sample container to be reached. Once the tag is applied, the sample container with the head including the sample attached, can be removed from the tag and placed within a protection tube including a closing cover so that the sample taken can be stored in a closed space bathed in appropriate substances and analysed later.
