The most intra species variation is found in dog eosinophils. Marked variation in granule size, number and shape occurs within and between individuals of any breed. Eosinophils in these breeds lack visible granules and appear as cells with slightly segmented nuclei, gray cytoplasm, and vacuoles. They are sometimes mistaken for toxic neutrophils or monocytes. Eosinophils of the cat have small rod-shaped orange granules that fill the cytoplasm, while those of the horse have very large globular orange granules.
Ruminant eosinophils have many small very round orange granules.