Final answer:
The animal viruses that can agglutinate red blood cells are known as myxoviruses, which include influenza viruses with hemagglutinin proteins that cause hemagglutination.
Step-by-step explanation:
The group of animal viruses capable of agglutinating red blood cells is the myxovirus. This is due to the presence of a particular protein on the surface of these viruses called hemagglutinin, which can cross-link red blood cells directly, causing visible clumping, also known as hemagglutination. Examples of viruses that belong to this group include influenza, which is known to have hemagglutinin spikes on its surface.