Did you ever have tonsillitis as a child? FACT: Sea lions have tonsils too! TONSILS are specialized lymph nodes that sample materials passing through the mouth or nose for the presence of infectious agents, and react (enlarge) to produce antibodies or immune cells if pathogens are encountered. Such reactive lymph node enlargement is called LYMPHADENOPATHY. Above is a photograph of the open mouth of a sea lion. The brown-stained TONGUE and black-pigmented TEETH can be seen in the foreground and the PALATE is above. In the very back of the mouth, two deep diagnonal clefts can be seen. These are the TONSILLAR CRYPTS, blind-ended sacs that contain the tonsils.