coloration:
the Trichechus manatus has a gray matte skin much like an elephant. however, due to its prolonged exposure to tropical waters, marine plant life is often found on the back of the manatee, adding green and yellow hues to the otherwise dull color.
physical size:
the Trichechus manatus is massive. from head to tail it measures 2.5 - 4.6m (or 7.7 to 15 feet long). even its skull can grow to as long as 67 cm. as a heavyweight at 350 to1600 kg (3.5 thousand pounds), it retains a certain luxurious mobility in the shallows. a signifigant part of our signifigant friend is blubber, which is used for both cold tolerance and energy storage.
unique features:
the Trichechus are the only mammals with 6 neck vertebrae -- every other mammal has seven.
the manatees do not use echolocation or sonar, and do not have vocal cords. but they do communicate vocally with high pitched sounds, scientists just haven't figured out how they do it yet.
the manatees are also unique in that they are the only mammals that undergo constant horizontal replacement of their molars. this evolved in part because the manatee's diet realies heavily on silicate-containing plants, which wore done the teeth.the manatees are also the only completely aquatic freshwater hervbivores.
the manatees, and other species in the order Sirenia, have very long intestines measuring 45 m or 150 feet in length.
manatees consume roughly 8 to 15% of their body weight daily. that's more than 160 kg a day!
humans killed another Sirenian in the 1700's, the Stellar's sea cow. this sea cow weighed almost 5 to 6 times as much as modern day Sirenians.
life span:
although manatees must live through relatively high mortality rates in youth years, scientists believe manatees could live over 60 years old. there is one manatee in captivity that is 52 years old.
reproduction:
the female manatees have a "receptive" period that lasts up to two weeks in which a mating herd of up to 17 unrelated males follows her closely. here male manatees probably compete for mating rights as an increase in violent behavior is noted. the larger the mating herd, the more chance of success the female has in securing a potential mate.
the typical gestation period following conception is about a year, giving birth to only one calf. the calf-cow bond is the strongest inter-manatee relationship, with dependency lasting 1 to 2 years.