Little is known around the ability of West Indian manatees come osmoregulate and maintain water balance, however previous research studies have argued that theyshould

be able to proactively d
rink salt water based upon urine data, your renal anatomy, and also their incident in naval habitats for prolonged periods. Absolutely manatees are generally seen “drinking” (or space they playing?) with water native hoses. Various other sirenian species are strictly fresh water residents (Amazonian manatees – Trichechus inunguis) or marine (dugongs – Dugong dugon). Due to the fact that West Indian manatees inhabit both fresh water and also marine environments, they administer an ideal species to deal with questions the water balance and osmoregulation in sirenians.

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We operated with captive West Indian manatees at framework in Florida and Brazil, as well as getting blood samples from free-ranging West Indian manatees in Puerto Rico and also Colombia. We wanted to see how manatees might cope v a variety of experimental conditions: pets living in new water eating lettuce (something through a an extremely high water content); pets living in salt water eat lettuce; and also animals life in salt water eating seagrasses (high in salt content and low in water content) with and also without access to fresh water come drink. In each case we measured how much new water castle drank and how lot they derived directly indigenous the food they to be eating (measured utilizing labeled water dilution) and also the capability of the animal to preserve electrolyte and also water balance.

Captive manatees organized in salt water without accessibility to fresh water and also fed a diet of sea grass showed far-reaching increases in plasma osmolality and also plasma concentrations of sodium and chloride in ~ 9 days. These manatees eventually refused come eat sea grasses. This data imply that wild manatees might require regular access to fresh, or probably brackish, water to fulfill water balance needs. In captive situations, this need is met by drinking new water or by eat food the is high in free water (e.g., lettuce, i m sorry is about 94% water). Manatees living in fresh water and consuming lettuce confirmed the greatest rate of day-to-day water intake (145 ± 12 ml kg-1 every day) contrasted to manatees in salt water top top a diet of lettuce (45 ± 3 ml kg-1 every day) or manatees life in salt water on a diet the sea grass (21 ± 3 ml kg-1 every day).

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This data imply that manatees living in new water no only get a good deal of water native the food they eat yet that lock are also drinking big quantities of water. Us were at some point able to demonstrate that manatees perform not proactively drink salt water, and also that incidental ingestion of salt water during feeding elicited common mammalian endocrine responses resulting in excretion that the overfill salt load.