West Indian Manatees Gallery

12-17-16

© Greg Amptman | Dreamstime.com

a

a

Their teeth are constantly being worn down by their very gritty vegetation diet. Adults have only molar teeth in two rows of six to eight teeth on their lower and upper jaws for a total of 24 to 32 teeth. The teeth are replaced continually for life with new teeth erupting at the back and moving forward as the worn (spit) teeth in front are discarded.

Manatee Tooth with Partial Roots (Fossil)

1860 Fd. Marion Co., Florida, USA

0.7"x0.6"x0.45" Crown

Manatee Atlas Vertebra (Fossil)
First Vertebra from Head 1874 Fd.Florida, USA

3.5"x5.3"x 1.4"

Manatee Axis Vertebra (Fossil)
Second Vertebra from Head 1854 Fd. North Florida, USA

3.4"x 3"x2"

Articulated Manatee Atlas and Axis Vertebrae (Fossil)
Same as shown separately above.

The West Indian manatees are one of three manatee varieties. They are gentle, peaceful, slow moving, aquatic mammals that primarily graze on aquatic plants. Adults grow to around 10 feet long and average between 800 and 1200 pounds. They have a streamlined body with a rounded horizontal paddle like tail for forward propulsion, and a pair of large flippers in front. The flippers are used for steering, walking on marine floor, putting food into its mouth, and touching. Manatees are quite agile in the water with the ability to swim on their backs, vertically, do somersaults, and rollover. They never leave the water.

The manatee has a very flexible upper lip that is split into two halves that can be moved independently allowing them to grab food. The lip has many thick whiskers attached to nerves that help in identifying and moving food. Horned like ridged pads behind the lips break down food to smaller pieces.[7] Food is further crushed by teeth in the back half of their lower and upper jaws.

Manatees have leathery, finely wrinkled thick skin that flakes off continually. This helps to keep algae and barnacles from building up on their bodies.[19]

West Indian manatees can live in saline and freshwater environments due to their kidneys ability to maintain proper salt and water levels in the blood. [20] They have little tolerance for cold water because of their low metabolism and lack of body fat."[21] Manatees cannot survive at temperatures less than 60 degrees F.[22] Florida West Indian manatees range from Virginia and Carolina to Louisiana in the warm summer months and return to Florida during the cold winter months.[23]Manatees may live to 60 years in the wild.

Small unattached pelvic bones are present that are often stated as vestigial in support for the idea that manatees were once land animals with four legs. However, such a claim assumes that the only reason to have a pelvis are legs. As in the case of whales not thought to be related to manatees, these unattached pelvic bones are needed attachment locations for certain muscles.

Manatee eyes are small and their depth perception may be not good.[12] They can detect objects tens of meters away in the water and distinguish blue and green colors and perhaps more.[13] Their eyes have no eyelashes and close in a circular manner. For protection, their eyes have transparent membranes that can be drawn over them and still allow some sight.[14] Their retinas contain rods and cones prerequisite to seeing in both bright and dim light.[15]
Manatees have no external ear lobes but they can hear very well.[16] They communicate through a wide range of squeaks, and squeals as well as touch and body language.

Worn Manatee Tooth (Fossil)

1109 Fd. location unknown, USA

0.6"x0.55"x0.2" Crown

Their immune system is very strong and manatee deaths from sickness are rare. Manatees do not seem to get cancer.[17]

Often stated is that manatees closest living relatives are elephants. Although, they have certain characteristics in common such as toe nails, skin color, wrinkled skin, teeth replacement mode, and flexible upper lip, similar characteristics do not prove evolution (macro evolution). These characteristics could have been used by the designer as desired on any number of animal kinds.

Manatees have no visible neck. They have six cervical vertebrae instead of seven like all other mammals, except sloths that have six or nine.[18] Having one less cervical vertebrae somewhat reduces the manatee's head movements.

Manatee Inner Ear Bone (Fossil)

1858 Fd. North Florida, USA

2.5"x1.8"x1.6"

They have a simple stomach and a large cecum to digest tough plant matter.[8] Manatees have a unusually long intestinal tract that is around 150 feet long. [wikipedia] Such a robust digestive tract is necessary because of the low nutritional valve of their marine plant diet.[9]"Manatees can survive on 25 percent less energy than an animal of comparable size..."[10]

Their flippers have bones similar to the human arm and hand including five jointed fingers with three or four nails that protrude through their thick skin.[11]

Manatee Flipper Bone (Fossil)

1879 Fd. Marion Co., Florida, USA

1.8"x0.85"x0.6"

Although they have a very small brain compared to their body size, they “are smarter than dogs and cats” and “probably as smart as pigs.”[1] “Manatees are capable of understanding discrimination tasks and show signs of complex associative learning. They also have good long term memory.”[2]

Like other sea mammals, they must come to the surface to breathe which they do every two to four minutes while active and up to every 15 to 20 minutes when resting. With each breath, the manatee replaces 90 percent of the air in its lungs as compared to humans that replace ten percent.[3] Their two nostrils are located on the top of their snout back toward their eyes and automatically close tightly when submerging. Manatee lungs are unique being flattened, about one third of the total length of their body long and placed along their backbone instead of near their ribs.[4] Their lungs also help with buoyancy and equilibrium. By compressing their lungs with their rib cage muscles, they reduce their lung volume making themselves more dense. This allows them to sink and surface almost effortlessly without actively swimming.[5] Incredibly dense marrow-less bones also help them sink.[6]

& Nature Photo Galleries

West Indian Manatee

Copyright 2016 All rights reserved.

A West Indian Manatee at the Crystal River, Florida