\u201cWhat we can say for sure is that manatees are sparsely represented in the archeological and historical records until the 1700s and 1800s,\u201d said Thomas Pluckhahn, a professor in the Department of Anthropology at the University of South Florida.<\/p>\n
Pluckhahn, a co-author of a new study\u00a0<\/a> on manatees published in PLOS One<\/em>, pored over records of manatee remains at archeology sites, as well as historical accounts of manatee sightings from newspapers and journals ranging from 12,000 BC through the mid-20th<\/sup> century. He attributes manatee population growth to a few factors, including warming ocean waters.<\/p>\n Temperature fluctuations\u00a0<\/strong><\/p>\n Pluckhahn said there was a centuries-long cold spell called the \u201cLittle Ice Age\u201d that began in the 1200s and lasted into the 1800s. He said that the effects of this are often debated, but studies of corals in the Caribbean suggest that water surface temperatures during that time were lower in the winter.<\/p>\n \u201cManatees are subject to cold stress even today, but you can imagine with the water temperature even a couple of degrees colder in the winter that would have been a limiting factor in their populations,\u201d he said.<\/p>\n Though the impacts of anthropogenic climate change on manatees are a mixed bag, warmer waters surrounding Florida have helped the species.<\/p>\n \u201cIt\u2019s made things more hospitable for manatees,\u201d Pluckhahn said. \u201cManatees need warm water. After going through newspaper accounts of when they started to be spotted more often in South Florida, they were being seen in yacht basins, canals and shallow water.\u201d<\/p>\n Residents in the Miami area even noticed that manatees were populating industrial outflows\u2014such as those surrounding power plants\u2014because of the warmer water, he said.<\/p>\n \u201cWe started building more and more power plants, and now those areas are critical refuges for manatees,\u201d Pluckhahn said.<\/p>\n