The present disclosure generally relates to the field of farming and more specifically the disclosure relates to methods and arrangements for automatically verifying identities of animals. According to a first aspect the disclosure relates to a method for updating reference data used by an animal identification algorithm designed to determine an identity of an individual animal in a population of animals with known identity. The method comprises obtaining identification images of the individual animal and executing the animal identification algorithm with metrics of the obtained identification images as input. The method further comprises, upon the animal identification algorithm determining the identity of the individual animal based on metrics of a subset of the obtained identification images updating the reference data based on metrics of one or more of the other identification images of the individual animal, not in the subset.
