What is one method to verify mating in breeding animals?

The presence of a copulatory plug in rodents is a reliable method to verify mating. This plug is a gelatinous mass formed from the male's ejaculate that hardens after mating. It serves as evidence that mating has occurred, as it typically obstructs the female's reproductive tract and prevents other males from mating successfully. This confirmation is particularly important in laboratory settings, where controlled breeding and accurate data collection are necessary for research purposes.

While the presence of offspring can indicate successful breeding, it does not provide confirmation until after gestation and delivery, which can be a lengthy process. Increased bending behavior in females is not a scientifically validated indicator of mating status. Visual inspection of the mating pair could suggest that mating is happening, but it does not provide the definitive evidence that the copulatory plug does, as mating might not have occurred even if the animals are observed together. Thus, observing a copulatory plug is the most direct and effective method for confirming mating in breeding animals, particularly in controlled environments like laboratories.