Manatees The Forgotten Mermaid

1. ManateesThe Forgotten Mermaid Janae Barrett

2. Figure 9.1

3. Figure 9.13

4. Classification: Kingdom- Animalia Phylum- Chordata Class- Mammalia Order- Sirenia Includes 5 species

5. 1. West African Manatee Range is the �crook� of Africa�s west coast Senegal & Angola mostly Small population Not well studied

6. 2. Amazonian manatee Only manatee that is a river-dweller Fresh water only Smallest of the 5 species Not well studied

7. 3. Dugong Indian Ocean and far Western Pacific in tropical environments All over N. Australia, Indo-Chinese, & Indian waters Hunted by aboriginal people of Australia Also found in Red Sea & East African coast Whale-like tail, instead of paddle-shaped Fastest of the 5 species

8. 4. West Indian Manatee 2 subspecies Antillean manatee Can range down to Brazilian coast from Caribbean islands in the North Florida manatee Primary range consists of Florida�s south coast Have been found from Mississippi to Virginia Both Atlantic and Gulf of Mexico sides 2 groups are isolated geographically

10. Major Characteristics Breast-feed young Mammary glands at corner of each flipper Nurse 1 offspring at a time for 1-2 years Gestation period of about 1 year Can hold breath for 20 min because of huge lungs on their dorsal side = can breathe easily on land too Front flippers are strong so they can drag themselves across shallow areas when water level is low 70 + year lifespan Breathe air with lungs Bear live young Possess hair Tough, thick skin Whiskers, called vibrissae, which serve as a sensory nerve function. Head is rounded Have a small mouth, & eyelids Very dense bones = heavy underwater to help them sink to feed

13. Evolutionary History Share a common ancestor with elephants, aardvark, & hyrax (large rodent) link made by common dental structure DNA evidence No collarbone Has vestigial pelvis from its land-dwelling ancestor Toenails & hooves rather than claws they have these on the end of flippers Males have small elephant- like tusks Snout is similar to elephant trunk & can articulate Teeth regenerate as they wear them down

14. Feeding Favorite food is water hyacinth Invasive species that chokes waterways in FL A few manatees can clear out a river in a few hours

18. Social Manatees Congregate in groups for long periods Been known to nuzzle people & investigate Only swims 15 mph maximum

19. Why are they endangered? In 35 million years of evolutionary history they haven�t evolved much They have no predators Alligators are outweighed Sharks rarely come that close into shore & waterways to attack them Current Causes of Decline 1. human impact: boats, habitat loss, etc. 2. thermal & chemical pollution

20. Causes of their Decline 1. Hit by boaters, & other harassment by humans Slow swimmers Surface-dwellers as they feed on macroalgae & freshwater plants Origin of nickname �sea cow� Motor noise likely falls into a frequency range they cannot hear Ears are buried inside the head, therefore they have difficulty detecting direction of a boat Chemical pollution of waters affects their immune system Loss of habitat due to human development

22. Causes of their Decline 2. Thermal & Chemical Pollution Tropical species without a lot of blubber Chemical pollution of waters affects their immune system Below 68�F water temp = hypothermia Susceptible to sun burn too Sometimes will drape head in seaweed or plants to cover up

23. Manatees & Power Plants Many power plants located on waterways in FL Use water to cool turbines, etc. Water is then pumped out (warmer) & manatees congregate in these areas to keep warm These areas may or may not have decent food supply for them Can get trapped in these warm areas with no food

25. Rescue, Rehab, Research, & Education Sea World, Orlando- has special pool with lift at bottom to raise them out of water enough to allow for procedures, etc. Lowry Park Zoo, Tampa- Vet. Dept has saved 80 indiv. since 1991- designed a neoprene suit to keep them warm while they recover Save the Manatee Club (assoc. with Audubon Society)- public education, Manatee Awareness Program for boaters, etc. Surveys ID animals by cuts & injuries & other skin markings- almost ALL adults have some scarring -skeg on boat motors does the damage not the propeller Radio-tagging by wrapping around the tail rise

26. Captive Breeding? It has been tried Unsuccessful in terms of support because it is a long-term process Don�t want calves born in captivity Once they are adults, almost 2 year later, they wouldn�t be able to cope in wild

27. Crystal River National Wildlife Refuge Largest population of manatees Major wintering spot Has become a tourist attraction Hot springs keep NWR waters warm Public allowed to snorkel & SCUBA with manatees Even tourist areas have NO PEOPLE zones & manatees seem to know where they are

30. Current Problems FL Senate & H. of Rep. has passed 2 bills in April 2004 that infringe on Nat�l Endangered Species Act & Marine Mammal Protection Act Pushed by boaters/ boating lobby in FL Want to change laws locally based on �local manatee population� �Local pop.� doesn�t exist because they migrate!

32. The Tragedy of Stellar�s Sea Cow Largest 25 feet long, 8,000-22,000 lbs Extinct Only species in cold climate Named for Georg Wilhelm Stellar Shipwrecked in Bering Sea in 1741 Rescued, shared this discovery 27 years later, hunted to extinction