Aardmonsters, in appearance have a type of biological appearance with some rarities applied to them, based on gender. This is also present in male leosapiens and some bird-based sapiens, known as "sexual dimorphism". This is a common characteristic in many animals in which the two sexes of the same species will exhibit different characteristics beyond the differences in their sexual organs. Male aardmonsters appear to have more noticeable markings in their fur coat and larger manes similar to that of a horse's mane while females rarely ever have such an appearance aside from rare hormonal disorders. This, of course means that females who have such a disorder will not only have the markings and mane of a male, but will also be 70% infertile. They typically have a dark, grayish blue, brown, or sometimes red shade of fur, with the exceptions of pigmentation disorders like albinism or melanism as examples.
Aardmonsters are described by other sapiens to be warm blooded, mammalian, plantigrade, monotreme creatures with long claws on their feet for gripping onto tree branches. They have claws on their front paws of similar size and length as the ones of their back feet for digging into the ground, in which they live in burrows like most sapien and non-sapien animals. They normally walk in quadrupedal movement, standing and stepping on the soles of their feet like bears, and the palms of their front paws. They will, however, occasionally stand upright on their back legs and use their front paws as hands to grasp, very similarly to monkeys, apes, raccoons, and humans.