Question 1

Mortality, Rescue and Rehabilitation Do manatees have a sense of smell?

Accepted Answer

While we don’t know for sure if manatees have a sense of smell that is comparable to humans or other mammals, manatees can likely smell and taste. However, these senses are reduced when compared to those of other aquatic mammals. A good sense of smell is helpful for animals that breathe air on land a lot, whereas manatees hold their breath underwater while they swim or eat and only come up to the surface occasionally to breathe. Researchers believe that manatees may use their sense of smell to detect other manatees, especially females in estrous, or "heat.” Learn more about manatee smell and taste. Do manatees have ears, and where are they located? A manatee’s ear is a tiny hole, located about the width of your hand behind the eye, with no external surface like our ears or elephant ears. Despite this, they are quite capable of hearing, and they are especially sensitive to high-pitched sounds like chirps, squeaks, and squeals, which they use for communication. High frequencies also allow them to determine the direction of sound, which is useful for finding their calves. Learn more about manatee ears and hearing from Wayne Hartley, Save the Manatee Club's Manatee Specialist. How can the age of a manatee be determined? A manatee’s age can be determined by the annual growth rings in its ear bones. Living manatees are classified as calves, subadults, and adults, and age can be approximated by birth date (if known) and their size. Learn more about estimating manatee age using growth layer groups in ear bones. Do manatees have good eyesight? Manatees’ eyes are small and they have a nictitating membrane that can be drawn across the eyeball for protection. They do not have eyelashes but rather open and close their eyes like the iris of a camera. Manatees have fairly good visual acuity and can distinguish between different-sized objects, brightness, and patterns. It is believed that manatees have rather poor visual acuity at close distances but better than expected visual acuity at medium or long distances. Manatees rely on direct contact for closer inspection rather than on sight, which can be problematic if they encounter objects such as monofilament fishing line, discarded fishing gear, and other trash. As manatees evolved, they adapted to live in murky waters and rely on more than one type of sensory system to investigate their underwater world. It’s safe to say that manatees do not rely on their vision as their primary sensory system; however, they may utilize their eyesight in combination with other senses to perceive their world in a way that benefits them beyond what we presently know. Do manatees see in color? Based on the internal structure of the manatee eye, which possesses rods and cones, manatees have color vision. Behavioral research has confirmed that they are able to see the colors blue and green against a grey background but are unable to see red. Manatees are believed to have dichromatic color vision. This characteristic is similar to that of California sea lions, fur seals, elephants, and hyraxes. Most other marine mammals have monochromatic vision. It is possible that the colors blue and green may be beneficial to enhance contrast and determine what might be edible in the manatees’ underwater world. Do manatees have teeth? Manatees do indeed have teeth. In fact, one of the most interesting things about manatees is that they keep replacing their teeth as long as they live. All of their teeth are molars. Called “marching molars,” their teeth are unique because they are constantly replaced. New teeth form at the back of the jaw, wear down as they move forward, and eventually fall out. This constant tooth replacement is an adaptation to the manatee’s diet, which often includes abrasive plants that are mixed with sand. Can manatees be left or right flippered? As far as we know, manatees do not show any dominance between a left or right flipper. So, we can’t say they are left or right-flippered in the way we may be left or right-handed! Learn more about manatee flippers from Wayne Hartley, Save the Manatee Club's Manatee Specialist. Is it true that manatees actually have fingernails? If it is true, how many do they have and why do they have them? Yes, manatees do have fingernails. They typically have about three to four nails on each flipper. However, only West African and West Indian manatees, including our very own Florida manatee, have fingernails. The Amazonian manatee and the dugong do not have fingernails. Dr. Daryl P. Domning, an expert on the evolution of sirenians and a member of Save the Manatee Club’s Board of Directors, explains this difference: “One could speculate that the nails might be helpful in preventing abrasion of the edges of the flippers when the animals use them to ‘walk’ along the sea bottom, as West Indian and West African manatees sometimes do, whereas the other species might do this less. Or the loss of the nails may have been for no directly adaptive reason. Since the nails (if any) of fossil sirenians have not been preserved, we can’t trace the actual time and circumstances of their loss.” Having fingernails is one of the many characteristics showing the similarities between manatees and their land relative, elephants. Elephants also have three to four nails on each of their feet, like our toenails. The reason manatees have fingernails is because they were once land animals and had forelimbs for walking on land. The bone structure of a manatee’s flipper actually looks very similar to a human hand. Their flippers are simply the evolution of forelimbs that once had fingernails, which they have retained over the years. How do manatees communicate with each other, and do they hear very well? On the whole, the sensory systems of the manatee have not been well studied. Anatomically, manatees have extremely large ear bones and may have a good sense of hearing. Manatees emit sounds underwater that are used in communicating with one another. It is not believed that they are used for navigational purposes. Vocalizations may express fear, anger, or sexual arousal. They are also used to maintain contact, especially when manatees are feeding or traveling in turbid water. Especially common are vocalizations between a female and calf. Manatee sounds can be described as chirps or squeaks, have peak energies in the 3-5 kilohertz range, and are probably produced in the larynx. It has been suggested, but not confirmed, that the most sensitive location on the manatee’s head for sound reception is not the tiny ear openings located several centimeters behind the eyes, but the area near the cheek bones, which are large and seem to be quite oily compared with other bones in the skull and which are in direct contact with the ear bones. This arrangement is similar to that of dolphins. In addition, anatomical studies suggest that manatees are not adapted to hear infrasound, frequencies too low to be heard by the human ear, generally less than 20 hertz. What is the “peduncle” of a manatee? The peduncle is the base of the tail, right where it connects to the body of the manatee. What is the average weight of a manatee? The average adult manatee is about 9.8 feet (three meters) long and weighs between 800 and 1,200 pounds (362 and 544 kilograms). What is the record weight of a manatee? Adult manatees have been known to exceed lengths of near 13 feet (four meters) and weigh over 3,500 pounds (1,587 kilograms). Manatees look really fat, but as they are not (after all, they feel the cold), is this “fattiness” actually muscles? Although manatees are big, they actually have very little body fat. Aquatic mammals that live in cold areas or deep water have developed better insulation than manatees require in their tropical home. A large percentage of the manatee’s body is taken up by the gastrointestinal tract, which contains the stomach and intestines. In fact, the gastrointestinal tract accounts for about 20% of the manatee’s body mass, and it produ

Question 2

” “Sea cow” is a common term for manatees and dugongs. This name likely comes from the fact that manatees are herbivores (plant-eaters), as are cows. What does the word “manatee” mean, and what are manatees called in various countries around the world?

Accepted Answer

It is believed that the word manatee comes from the Carib word “manati,” meaning “(woman’s) breast.” Carib is a language indigenous to South America and is spoken in Venezuela, Brazil, French Guiana, Guyana, and Suriname. Manatees are known by a variety of names in other languages as well. In Spanish, which is spoken by several Central and South American counties where the West Indian manatee is found, manatees are known as “manatí.” Portuguese is the official language in Brazil, where manatees, or “peixe-boi,” can be found in the Amazon River or along the coast. Crossing over the Atlantic Ocean, the West African manatee is commonly known as “mamiwata.” This is in reference to a female water-spirit found in some African cultures, particularly in the western coastal regions and central Africa. French is also spoken in many countries in West Africa, including Senegal, where West African manatees are known as “lamantin” in French. What does Trichechus mean in the manatee’s scientific name? Dr. Daryl P. Domning, an expert on the evolution of sirenians and a member of Save the Manatee Club’s Board of Directors, provides the answer to this question: The name Trichechus means “hairy” and was originally coined by Peter Artedi in 1738 in his book Ichthyologia (=Ichthyology). (This was before Linnaeus used it as part of a binomial name in 1758, whence we get the official modern zoological usage.) It included both manatees and dugongs, under the heading of “fish” in the broad sense, and was meant to distinguish these “fish” with hair from the other fish having scales.

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Mortality, Rescue and Rehabilitation Do manatees have a sense of smell?

” “Sea cow” is a common term for manatees and dugongs. This name likely comes from the fact that manatees are herbivores (plant-eaters), as are cows. What does the word “manatee” mean, and what are manatees called in various countries around the world?

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