The page title is not present in the lead - see MOS:TITLEABSENT← Previous revisionRevision as of 14:24, 4 November 2026 Line 7: Line 7: [[Image:Trichechus manatus fg01.JPG|thumb|right|300px|The foot of a manatee. Manatees are believed to share common ancestry with [[elephants]].]] [[Image:Trichechus manatus fg01.JPG|thumb|right|300px|The foot of a manatee. Manatees are believed to share common ancestry with [[elephants]].]] '''[[Sirenia]]''' is the [[order (biology)|order]] of [[Eutheria|placental mammals]] which comprises modern "sea cows" ([[manatee]]s and the [[Dugong]]) and their extinct relatives. They are the only extant [[herbivorous]] [[marine mammal]]s and the only group of herbivorous mammals to have become completely aquatic. Sirenians are thought to have a 50-million-year-old [[fossil]] record (early [[Eocene]]-recent). They attained modest diversity during the [[Oligocene]] and [[Miocene]], but have since declined as a result of climatic cooling, oceanographic changes, and human interference.{{Cite book|title=Return to the Sea: The Life and Evolutionary Times of Marine Mammals|last=Berta|first=Annalisa|publisher=University of California|year=2012|isbn=978-0-520-27057-2|location=Berkeley, CA|page=5}} Two genera and four species are extant: ''[[Trichechus]]'', which includes the three species of manatee that live along the [[Atlantic Ocean|Atlantic]] coasts and in rivers and coastlines of [[the Americas]] and western [[Africa]], and ''[[Dugong]]'', which is found in the [[Indian Ocean|Indian]] and [[Pacific Ocean|Pacific]] oceans.{{citation needed|date=August 2012}} [[Sirenia]] is the [[order (biology)|order]] of [[Eutheria|placental mammals]] which comprises modern "sea cows" ([[manatee]]s and the [[Dugong]]) and their extinct relatives. They are the only extant [[herbivorous]] [[marine mammal]]s and the only group of herbivorous mammals to have become completely aquatic. Sirenians are thought to have a 50-million-year-old [[fossil]] record (early [[Eocene]]-recent). They attained modest diversity during the [[Oligocene]] and [[Miocene]], but have since declined as a result of climatic cooling, oceanographic changes, and human interference.{{Cite book|title=Return to the Sea: The Life and Evolutionary Times of Marine Mammals|last=Berta|first=Annalisa|publisher=University of California|year=2012|isbn=978-0-520-27057-2|location=Berkeley, CA|page=5}} Two genera and four species are extant: ''[[Trichechus]]'', which includes the three species of manatee that live along the [[Atlantic Ocean|Atlantic]] coasts and in rivers and coastlines of [[the Americas]] and western [[Africa]], and ''[[Dugong]]'', which is found in the [[Indian Ocean|Indian]] and [[Pacific Ocean|Pacific]] oceans.{{citation needed|date=August 2012}} == Origins == == Origins ==