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Florida manatee images (Trichechus manatus latirostris) - stock photos & facts of the largest surviving species of aquatic mammal of order Sirenia Conservation status | Vulnerable
- Overview
- Natural history
- Classification and paleontology
sirenian, (order Sirenia), any of four large aquatic mammalian species now living primarily in tropical waters where food plants grow. The three species of manatee (genus Trichechus) occupy warm latitudes of the coastal Atlantic and associated rivers, and the dugong (Dugong dugon) inhabits the coastlines of the Indian and Pacific oceans. The extinc...
The order Sirenia was named after the Sirens of Greek mythology, and sirenians are believed to be the basis for the mermaid myth. Modern sirenians have two front limbs in the form of flippers but no hind limbs; even the pelvis is vestigial, and there are no skeletal remnants of leg or foot bones at all. Sirenian bodies are basically round in cross-section and taper toward the tail, which is flattened horizontally and provides propulsion. Dugong tails are deeply notched, similar to those of whales, whereas in manatees the tail is rounded outward like a paddle. Sirenians in general are slow-moving but capable of short bursts of speed. There are no marked differences between the sexes; females have two inconspicuous mammary glands with one teat near the base of each flipper. Both dugongs and manatees have thick tough skin (that of Steller’s sea cow was even tougher). All sirenians are nearly hairless except at the muzzle, where there are thick sensory hairs called vibrissae. The upper lip is enlarged and muscular and serves to grasp and manipulate food plants. The eyes are small, and the external ears consist only of tiny pits. Nostrils on the upper surface of the snout function as valves to exclude water. Sirenian bones are exceptionally dense, most of them lacking marrow. This adaptation is thought to help maintain neutral buoyancy.
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Manatees and dugongs differ in a number of traits besides the shape of the tail. Manatees lack incisor teeth, but incisors do occur in dugongs, erupting as tusks in the males. Manatees grow a never-ending series of molars that continuously move forward in the jaw to replace those that wear and fall out at the front. Dugongs, on the other hand, have a finite number of six molars and premolars in each jaw, and they are not replaced; in older individuals only two remain. Manatees have six neck vertebrae instead of the seven typical of mammals. Dugongs are exclusively marine, but manatees inhabit both marine and freshwater systems.
Sirenians arose from terrestrial hoofed mammals (tethytheres) during the Paleocene Epoch (65 million to 54.8 million years ago) in what is now the Old World. Tethytheres also gave rise to elephants (order Proboscidea), and early sirenians spread to shallow waters throughout the tropics. The family Dugongidae, which eventually included Steller’s sea cow, was an early offshoot, giving rise to the Trichechidae about 40 million years ago.
•Order Sirenia (sea cows) Four living species in two families
•Family Trichechidae (manatees)
•Genus Trichechus Three species
•Family Dugongidae Two genera, one now extinct
•Genus Dugong (dugong) One species
1 day ago · This same behavior was documented in the late 1800s and early 1900s, when newspapers reported on manatees hanging out in warm areas like canals and yacht basins, as well as near sewage plants.
The West Indian manatee (Trichechus manatus) or “sea cow” is the largest surviving member of the aquatic mammal order Sirenia. There are two subspecies of this animal: the Florida manatee and the Antilles or Caribbean manatee. Like other sirenians, this manatee lives entirely in water. Hence, they have no hind limbs.
Adult manatees are 3 meters long on average (10 ft), and weigh an average of 500 kg (1,100 lbs). Some individuals reach a length of 4.6 meters (15 ft), and a weight of 1,000 kg (2,200 lbs) or more. Females are typically larger and heavier than males.
Sirenia are elephants, aardvarks, and hyraxes, small furry mammals that resemble rodents. More than a dozen sirenian genera are known from the fossil record, so this order was once much more diverse and widespread than it is today (Dawson 1967). The fossil record shows that both manatees and dugongs were once found in the Caribbean and western
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Dec 22, 2023 · Sirens morphed over the millennia into mermaids, a myth for which manatees have occasionally been credited as originators. Although the disconnect between the mythological depiction and the manatee’s actual appearance somewhat belies the idea, it is almost certain that many sightings of mermaids by sailors during the Age of Discovery were, in fact, of manatees.
