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. 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 Major Characteristics

11. Manatee calf nursing

12. Manatee Skeleton

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

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

24. Manatees in Florida Inland locations are aquariums or research facilities.

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