Gentle Giants and Graceful Grazers; A Look at the Florida Manatee

The Florida manatee, Trichechus manatus latirostris, is known for its gentle nature and lumbersome ways. Its nickname, the sea cow, comes with good reason. This mammal spends nearly 8 hours out of its day doing nothing but eating, yes nothing but eating. During these 8 hours of munching, the manatee can consume about 7.5% its own body weight in food per day. Their diet consists of over 60 different types of aquatic plants including turtle grass, mangrove leaves, and types of algae. That is a lot of food considering adult manatees can reach nearly 10 feet long weighing in at around 1,500 lbs. That is a big cow! A unique aspect of the manatee is that it is the only herbivorous mammal that is specifically designed to live the entirety of its live in the water.

The Florida manatee is found in the southeastern part of the U.S. mainly in Florida. Its main habitat consists of coastal wetlands and the warm waters of shallow rivers, bays, and estuaries. They can be found in several different parts of Florida including the North and Southwestern Florida, the Atlantic coast, and St. Johns River along with the Gulf. In these areas, not all of the water is salt water and the sea cows can survive in saltwater as long as there is freshwater nearby and available. They are also found in brackish areas. During the winter months, they will travel further into the gulf and gather in the rivers and the natural springs located there. The internal temperature of a sea cow is 97.5 degrees Fahrenheit and if the temperature of the water that they are in reaches below 65 degrees Fahrenheit, they can get "cold stress syndrome" and can possibly die.

While in the water, manatees have been clocked at swimming nearly 20 miles an hour, however they typically only swim at around 3-6 miles per hour, doing somersaults and barrel rolls and can be seen gliding through the water upside-down. To swim, the manatee uses its forearms that are reduced to simple paddles that are used for steering and also are flexible enough to help bring food towards its mouth and to scratch their eyes and face. These paddles each have 4 nails at the tip of each and the rear paddle, or tail, is where the manatee gets its power while swimming. Although the manatee is designed to live in the water for its entire life, it does take breaks from eating and sleeping to come to the surface and take a breath. In fact, the manatee takes a breath every 3 to 4 minutes during activity but can hold its breath for up to 20 minutes during rest. The reason that a manatee can hold its breath for so long is because the lungs in an adult can reach nearly 3 feet in length and when it takes a breath, it can replace up to 90% of the air versus humans who only replace 10%. This air also aids in buoyancy.

Another really cool aspect of the manatee is that its bones are solid and do not contain any marrow or hollow cavities and this is too help the manatee be able to sink to eat the aquatic plants off of the river bed. The bones help to indicate age as well with the growth layers. In the wild, a manatee can live upwards of 50-60 years and in captivity just short of around 65 years. Their lifespan is so long because the manatee has not natural predators and its only threat are people and the cold weather. Boat propellers and jet skis are a huge threat to the manatees along with habitat destruction. The numbers of manatees is declining in the wild because of those previously mentioned and also because they have a very slow reproduction rate. They only have one calf every 5-7 years with a 12 month gestation period. Females also do not typically breed until the age of 6-10 years.

Sea cows are gray to brown in color with small, widest set eyes and they have ears that lack external lobes. Since they eat so many plants, they are hind-gut fermenters with a very long digestive tract. Because they are constantly eating, they need to have great teeth to withstand the grinding. With this wear and tear on the teeth, they continuously replace their back molars. The molars erupt from the back of each jaw and pushes forward, forcing out old teeth at the front .

I looked at a study done at the University of Florida on the material properties that make up the rib in manatees. This is so interesting because the ribs in manatees are completely solid to help with the density to sink the bottom to graze without using mush energy. However, even though they sink to eat, they still get hit by boats and other water craft. This is analyzing what kind of impact these bones can withstand to be able to better mark speeds that boats can travel in manatee areas. The results show that manatee bone is not as strong and tough as other mammalian bone. Their bones cannot absorb much in the way of energy or impact leading to more fatalities of these creatures when hit by boats. This decrease in energy absorption is because of the density and mineral content of the bone. This was tested by examining the strength, modulus, work of fracture and fracture toughness.




Sources-

Manatee Info- http://www.cincinnatizoo.org/animals/mammals/floridamanatee.html

http://www.defenders.org/wildlife_and_habitat/wildlife/manatee.php

http://www.sirenian.org/FPLBooklet.pdf

Manatee rib study- http://journals.ohiolink.edu/ejc/pdf.cgi/Clifton_K._B.pdf?issn=09528369&issue=v274i0002&article=150_mpomrb

The Red Panda

Red Panda

Ailurus fulgens

Habitat:

Red pandas live in the Himalayan Mountains in bamboo forests, spanning across Nepal, India, Bhutan, and Myanma. They enjoy the moist cool air at elevations of 7000-15500 feet.

Food Source:

Like there giant panda relative the red panda survives mostly on a diet of bamboo. They must constantly eat in order to maintain their body weight, even eating up to 200,000 bamboo leaves a day.

Intriguing Facts:

They have an incredibly low metabolic rate, similar to that of a sloth. So this animal rests up in the trees for almost 15 hours a day. They spend almost all of their waking time eating. They are solitary creatures, only coming in contact with other red pandas during mating season. Due to habitat loss the red panda is one of the most endangered species on the planet, it is estimated only 2500 individuals remain.

Resent Research:

The current phylogeny of the red panda is debated. Some scientist debate that it is more closely related to the raccoon, while others suggest it is more closely related to the bear. Others still suggest that it should be placed in a family all its own. The research done by the Chinese University of Science seeks to better understand the red pandas elusive phyologeny. They analyzed the: “interchromosomal rearrangements and amplic-cation of repetitive sequences have played a major role in differentiating the karyotypesof the mustelid species.” Their results showed that the red panda is closely related to the mustelids, or weasel family. This is certainly an interesting find and more genomic research is currently being done, fossil analysis must also be done to confirm the phylogeny thoroughly.

Sources:
General info- http://www.edgeofexistence.org/mammals/species_info.php?id=19 and http://www.centralparkzoo.com/animals-and-exhibits/animals/mammals/red-panda.aspx

Research- http://www.springerlink.com/content/uvnvj8x37ytcmnkt/

Special Little Swimers

The otter is one of my favorite animals not only because its cute but because it is interesting. The otters we saw at the zoo are North American River Otters(Lontra Canadensis) which obviously live in North America as the name says. They can be found in most rivers throughout the entire continent and exist here in Ohio. They usually eat fish, crayfish, and crabs since they spend most of their time in the water but can occasionally eat small birds and rodents. They are very specialized for water life and are able to close their ears and nose, have a clear third eyelid called a nictitating membrane, webbed feet, and they can hold their breath for up to 8 minutes. They also have claws that are useful if they happen to venture onto land or need to build their dens.

In a recent study researchers studied the patterns of these otters moving throughout Minnesota. A group of otters was monitered for multiple seasons and things such as time of day, temperature, weather etc. were observed. The otters were most active in the evening and least active around mid-day. It was also found that there was more activity during mating season and less during winter. Although there was less winter activity in general there was more foraging for food probably because of the increased energy needs for temperature regulation. There was also increased activity in males compared to females. Although the authors hypothesize that it may be because of differing diets, or different energy needs they did not test these hypotheses.


Zoo otter info
Otter research study

The North American River Otter (Lontra canadensis)

Basic Information
These very social, playful aquatic animals are members of the weasel family of the order Carnivora. Their bodies are highly modified for a life spent mostly in and around the water. These modifications include a streamlined body, webbed feet, thick, water-repelling, insulating fur, a tapered tail, and small ears and nasal openings that can close underwater!

Habitat and Range
These river otters live in mainly the northern U.S., the coastal states, and parts of Canada in and close by any inland waterways.

Diet
River otters will eat many different types of freshwater creatures including fish, crayfish, small mammals, frogs, mollusks, and other small invertebrates.

Life History
Females give birth to one to six young in their underground burrows. Males do not take part in the care of the young. After about 2 months of mainly being in the burrow, the mother pushes the young otters into the water, forcing them to learn how to swim while she supervises.

Primary Research
I looked at two current research articles on the North American River Otter, one explored the impact of an invasive trout species on the otter populations in Yellowstone National Park and the other was written about an attempt to reintroduce the river otters to waterways in Indiana.

The paper about the invasive species of Lake trout being found in increasing amounts in several lakes in Yellowstone National Park, revealed that although some other species of piscivores (fish-eaters) such as the grizzly bear and some birds are being impacted by the replacement of the endangered Yellowstone cutthroat trout with the invasive lake trout, the river otter is doing fine. The river otter eats a variety of different fish, so replacing one of its major food types with the invasive species of trout does not change anything except now more of the river otter's diet is made up of lake trout rather than the cutthroat trout.

The second paper spoke about the attempt to reintroduce the North American river otter to Indiana after the species had disappeared from the state in 1942 due to fur trapping, loss of habitat, and food. The attempt had mixed results in that many of the original otters introduced from surrounding states were killed by various means just as they were before. However, some good was achieved and many of the otters did begin breeding and establishing themselves in certain regions of the state. The paper stated that the researchers conducting this experiment did need to look further into ways to protect, maintain, and regulate these restored populations as well as defining the exact occupied regions and certain age-specific reproductive patterns.

Resources

1. http://animals.nationalgeographic.com/animals/mammals/american-river-otter.html
2. Kelt, D; Johnson, M. (2010) Ecological consequences of invasive lake trout on river otters in Yellowstone National Park. BIOLOGICAL CONSERVATION, 143, 5, p. 1144-1153.
http://journals.ohiolink.edu/ejc/pdf.cgi/Wengeler_William_R.pdf?issn=00063207&issue=v143i0005&article=1144_ecoiltroiynp
3. Walker, H; Hudson, C; Hewitt, T; Thompson, J. (2007) Prospects for restoring river otters in Indiana. Proceedings of the Indiana Academy of Science, 116, 1, p. 71-83.
http://web.ebscohost.com/ehost/pdfviewer/pdfviewer?hid=18&sid=a7a05636-c0b2-4db4-b24a-160dd978c61a%40sessionmgr15&vid=2

This Should Lure You In.....

The alligator snapping turtle, Macrochelys temminckii, is found in lakes and streams in the south eastern region of the United States and can be found into Canada. The largest specimen ever formally recorded was a 236 pound alligator snapper at the Brookfield Zoo in Chicago. On average, these turtles generally grow to a carapace length of 26 inches and weigh up to 175 pounds. These turtles got their name from the three pronounced ridges that are on the carapace which resemble those of the alligator. Often called the dinosaur of the turtle world, these interesting turtles are very primitive in appearance. These turtles can live anywhere from 50-100 years!

Alligator snapping turtles are scavengers by night and hunters by day. During the day, the use a specialized section of their tongue, which resembles a worm, to lure in prey. When the lure is in use, it fills with blood giving it the red color of a worm. To help with camouflage, the deep ridges of the turtle's shell become covered with algae helping to blend their shell into the substrate. The inside of the turtles mouth is grey in color and also blends in with its surroundings.

These turtles mate in early spring and nest 2 months later. The female will lay her eggs about 50 yards from the water's edge and this is the commonly the only time these turtles will leave the water. A clutch of eggs can contain 8-52 eggs and incubation lasts anywhere from 100 to 140 days. Sex is determined by the temperature of each individual egg during incubation.

A study produced by the Louisiana Department of Wildlife and Fisheries in 2006 titled "Food Habits of Macrochelys temminckii from Arkansas to Louisiana" includes interesting information on the food habits of these interesting turtles. This experiment was carried out by investigating the stomach contents and intestinal tracts of 109 alligator snapping turtles from both Arkansas and Louisiana. One of the first findings of the study was that a positive correlation between body mass and stomach content was discovered. This means that the larger a turtle was, the more food it consumed. Contents of the stomach and intestinal tracts included the following in order of most common: fish, crayfish, mollusks, turtles, insects, and nutria. Most surprisingly mammals were found in the digestive tracts of these primitive looking turtles. It is just another connection to the alligators from which they got their common name. Mammals that were found in their stomach include; Dasypus novemcinctus (armadillo), Didelphis virginiana (Virginia opossum), Sciurus sp. (squirrel), and Sus scrofa (hogs). The take home message from this study is that alligator snapping turtles are opportunistic scavengers and have the ability to consume a wide variety of prey.


Sources:
Turtle info: http://animals.nationalgeographic.com/animals/reptiles/alligator-snapping-turtle/
http://www.tortoise.org/archives/snapping.html
Louisiana Study:http://web.ebscohost.com/ehost/pdfviewer/pdfviewer?vid=4&hid=17&sid=9c803ba8-173d-4f22-82b9-5300ed2f3730%40sessionmgr12

Caribbean flamingo

Caribbean flamingo
Phoencopterus ruber ruber

Habitat: North and South America; mud flats, shallow lakes, and salt lagoons

Food source: Filter feed on algae, crustaceans, seeds, small fish, insects, and mollusks

Interesting facts: Both male and female flamingos produce crop milk which is used to feed the juvenile flamingos while they are young. Flamingos typically only lay one egg at a time.



Recent research: There has always been a common question surrounding the way that flamingos rest. Flamingos are known for resting on one leg. The common question is: Why do the flamingos only stand on one leg and not two. Recently studies (Anderson 2009) have found that resting on one leg may help the flamingos in thermoregulation.

Because flamingos are filter feeders, they heavily rely on the health of their beak and tongue to survive. Another fairly recent study (Hammer 2007) showed that if flamingos eat foods that are too greasy, they can have a build-up that will hinder their filter feeding ability.


Anderson, Matthew J. and Sarah A. Williams. “Why do flamingos stand on one leg?” Zoo Biology 29:365-374 (2009).

Hammer, Sven, Simon Jenson, Raffy Borjal, and Marcus Clauss. “Bill impaction in a group of captive Caribbean flamingos (Phoenicopterus ruber).” Journal of Zoo and Wildlife Medicine 38(3): 465-470 (2007).

Alligator snapping turtle

Physical description

With large heads and powerful jaws, alligator snapping turtles (Macrochelys temminckii) are the largest freshwater turtles in the world.  They can be easily distinguished by the three large pronounced ridges that run from front to back on the carapace. The fact that they have eyes on the sides of their heads makes them unique.

[Picture of an alligator snapping turtle (M. temminckii) that I took while at the Columbus Zoo]

Habitat

Alligator snapping turtles live in freshwater areas in the southeastern United States. Adults live in deep lakes and ponds, while juveniles are usually found in smaller rivers and streams.

Diet

Alligator snapping turtles are hunters and sometimes scavengers. They sit still with their mouth open, using their tongue to lure in fish. Alligator snapping turtles will also eat molluscs, crayfish, insects, leaves, roots, tubers, nuts, and seeds, and aquatic plants, but their diet mainly consists of fish. They may even eat other turtles; in one Louisiana study, turtles were found in the stomachs of just under 80% of all alligator snapping turtles.

Habitat Study

By attaching radio transmitters to alligator snapping turtles in Arkansas, Howey and Dinkelacker found how they choose habitats throughout the year. Both males and females showed a high preference for aquatic sites with large amounts of submerged debris and canopy cover. This may be due to increased prey abundance near debris and higher chance of nuts and seeds falling from canopy cover. Also, more cover allows for more places for the alligator snapping turtles to hide from predators. Howey and Dinkelacker also found that both sexes prefer deeper water or stream banks during the summer months for easier thermoregulation. This allows them to sun themselves to warm up, and go underwater to cool off.

Sources:

AnimalDiversityWeb. (2010, November).  Macrochelys temminckii. Retrieved November 29, 2010, from

http://animaldiversity.ummz.umich.edu/site/accounts/information/Macrochelys_temminckii.html

Howey, C. A. F. & Dinkelacker, S. A. (2009). Habitat Selection of the Alligator Snapping Turtle (Macrochelys temminckii) in Arkansas. Journal of Herpetology, 43(4), 589-596. doi:10.1670/08-105.1

http://journals.ohiolink.edu/ejc/article.cgi?issn=00221511&issue=v43i0004&article=589_hsotasttia&search_term=%28Alligator+snapping+turtle%29