Evolution Fossil remains of manatee ancestors - also known as sirenians - date back to the Early Eocene. It is thought that they reached the isolated area of the South American continent and became known as Trichechidae. In the Late Miocene, trichechids were likely restricted in South American coastal rivers and they fed on many freshwater plants. Dugongs inhabited the West Atlantic and Caribbean waters and fed on seagrass meadows instead. As the sea grasses began to grow, manatees adapted to the changing environment by growing supernumerary molars. Sea levels lowered and increased erosion and silt runoff was caused by glaciation. This increased the tooth wear of the bottom-feeding manatees.
evolutIoN foSsil remaINs Of mAnatEe ancestors - AlsO KnoWN as sireniANs - dAte back to The EArly eocene. It iS ThouGHT tHaT they reaCHed the iSOLATEd area of thE south amEriCan ContIneNt And BEcame known as trichechIdaE. iN thE latE mioCEne, trIcheChids wErE LikElY REsTriCtEd iN sOuth american coaSTAl riveRS AnD TheY fed On mANy Freshwater pLAntS. dugoNgs inHAbiTeD the WEst aTlantiC AND carIbbEan waTers aND FEd ON seagrass meAdows INstead. AS tHe sea GRassEs BEgan to grow, manAtees AdApted tO tHe cHaNgInG enviRONment BY groWing superNumeRArY Molars. sea levels lowerEd and increaseD ErOSIon aND Silt rUnoFf WAs CauSed bY glaciation. This IncReased ThE ToOTH WEaR Of The botTom-FeedINg MAnAtEeS.