Insectomammals were species which had features of both mammalian and insectoid species. Keerzachi were a sentient example of insectomammals. Insectomammals often combined insectoid characteristics such as exoskeletons, antennae, mandibles, egg-laying, and open circulatory systems with mammalian characteristics such as skin, teeth, hair, delivery of live young, and closed circulatory systems. The exact combination of traits varied from species to species.