Scales serve as a sort of armor for fish. Lumpsuckers (Eumicrotremus orbis) take that concept a step further, sporting spiny protrusions that were once thought to be made of keratin — the same substance found in human hair and nails — but recent research has revealed to be enamel. “Lumpsuckers are covered in teeth!” University of Washington scientist Karly Cohen, who co-authored the study, told WTTW News.

In that way, lumpsuckers resemble sharks, whose skin is blanketed with flat V-shaped dermal denticles (aka, “tiny skin teeth”). That’s where the similarity between the two fish ends, though. Denticles decrease drag so sharks can swim faster. Whereas lumpsuckers, well ...