Alligators, Crocodiles, and Hippo’s

1. Alligators, Crocodiles, and Hippo’s

2. What is this?

3. What is this?

4. What is this?

5. What is this? • Caiman

6. Which one is which?

7. Crocodilians • Alligators, caimans, crocodiles and gharails are jointly referred to as CROCODILIANS

8. Crocodilians

9. Crocodilians • About 20 species of crocodilians all of which are lizard like, egg laying, eat eaters • Largest modern reptiles they constitute the last living link with the dinosaur like reptiles of prehistoric times • Live in water but also travel on land by sliding on their bellies, stepping along with their legs extended or galloping awkwardly

10. Crocodilians • Large adults can stay under water for over an hour without breathing • Swim primarily by snakelike movements of their bodies and by powerful strokes of their muscular oar like tails (also acts as a weapon) • When float in water they leave only their nostrils, eyes, and ears above the surface. Eyes can be covered with semitransparent membranes and the ears and eyes are closed over by folds of skin

11. skin Crocodilians They control the depths at which they float by controlling the amount of air they retain in their bodies 

12. American Alligator

13. American AlligatorsPhysical Traits • Belongs to the family Alligatoridae • American Alligator (Alligator mississipiensis) inhabits the Southeastern United States from North Carolina to Florida and west to the lower Rio Grande. • Chinese Alligator (Alligator sinensis) is found in the Yangtze River Valley of China

14. American AlligatorPhysical Traits • Inhabit large shallow lakes, marshes, ponds, swamps, rivers, creeks, and canals in fresh and brackish water area

15. American Alligator Physical Traits • Elongated armored, lizard-like bodies with muscular flat tails • Broad head with a long, wide, rounded, shovel-shaped snout (shorter than a crocodile). Nostrils at the end to allow breathing while submerged under water.

16. Alligators Physical Traits • Their eyes and nostrils close by reflex when the animal goes underwater. • They have a transparent third eyelid, or nictitating membrane, that covers the eye as the animal moves through the water. • Valves to close the ears and nostrils when it is submerged

17. Alligator Look at Nose, Eyes, and Ears

18. Alligators Physical Traits • Four short legs – five toes on the front feet and four on the rear • Skin on their backs is armored with rows of bony plates called osteodermsor scutes • Average adult size – 8.2 feet for females and 11.2 feet for males • Can weigh more than one ton

19. Alligators Physical TraitsHow many toes?

20. Alligators Physical TraitsHow many toes?

21. Alligator Traits • Young hatchlings have bright yellow stripes and blotches

22. American AlligatorPhysical Traits • Adults are dark with pale undersides • Do not have a tooth that shows outside of the mouth when closed • Poikilothermicor ectothermic having an internal temperature similar to their surroundings (formally called cold blooded}

23. AlligatorsFeeding Habitats • Alligators are carnivores • Young alligators eat insects, snails, frogs, small fish, and invertebrates. • At a length of 6 feet they feed mainly on fish, turtles, snakes, water birds and small mammals. • An adult will eat 20 lbs per week in hot weather, but no food during the winter. • Large alligators readily eat carrion (dead flesh) and in fact prefer it to fresh meat.

24. Alligator eating a turtle.

25. AlligatorsFeeding Habitats • They are opportunistic feeders and will eat almost anything including such objects as sticks, stones, fishing lures, and aluminum cans

26. AlligatorsReproduction • Sexual maturity depends on the size of the alligator – about 6 feet. Wild alligators will be about 10-12 years old. For alligators raised in captivity it will be much sooner • Mature alligators seek open water areas in April and May – courtship and breeding season • Males roar during the mating season, but the normal vocalization is a hiss.

27. Alligators Mating

28. AlligatorsReproduction • After mating females move into marsh areas to nest in June and early July • Females construct mounded nests of available vegetation. They lay between 35-50 eggs (There may be as few as 1 or as many as 88) • After laying eggs the female covers the eggs with a layer of vegetation

29. AlligatorsReproduction • There is a 65-day incubation period. Females stay nearby their nests and defend their eggs against predators such as raccoons. Only fifty percent of the eggs will survive. • Females are territorial and will guard and defend their nests.

30. AlligatorsReproduction • Eggs hatch in mid August – mid September. The young alligators make high-pitched grunting sounds from within the egg. Females respond by using their mouths to remove the nesting materials covering the young thus liberating 6-8 inch hatchlings

31. AlligatorsReproduction • Hatchlings remain in groups called pods at least through the first winter and may stay near the nest site for 2-3 years • First 2 years of life is the most critical. Birds, raccoons, bobcats, otters, snakes, large bass or even large alligators may eat 80 % of the hatchlings

32. AlligatorsReproduction • Once an alligator exceeds 4 feet it is relatively safe from predators but is still vulnerable to cannibalism

33. AlligatorBehavior • Are apex predators • Thermoregulate – sun themselves during the day and go into the water at night • Lead solitary lives establishing individual territories

34. Alligators and Humans • Alligators have been hunted for meat and skins (Handbags, luggage, shoes, belts, etc.) • Today through strict laws alligators may be harvested during very limited controlled hunts and are raised in captivity for the production of meat and skins

35. Alligators and Humans • Urbanization in Florida has increased the contact between alligators and humans (For example they are found in pools, on golf courses, ditches, etc.) • Risk of being attacked is low (especially 4 feet or less, over 6 feet is a greater hazard) • Most attacks occur because humans feed alligators or when they are defending their nests

36. Solutions • DON’T swim outside of posted swimming areas in water that might contain large alligators. DO swim in designated areas only • DON’T swim at night or dusk when alligators most actively feed. DO swim during the day and avoid areas of thick vegetation near the shoreline

37. Solutions • DON’T feed alligators. They lose their natural shyness and become attracted to humans when fed

38. Solutions • DON’T throw fish scraps into the water or leave them on the shore. DO dispose of scraps properly • DON’T allow pets to swim near waters known to contain large alligators • DO report nuisance alligators (more than 4 feet in length that appear to have lost their natural fear of people or otherwise pose a threat to people or property) to the Florida Game and Fresh Water Fish Commission

39. Legal Aspects • American alligators are listed by the state of Florida as species of concern and by the Federal Government as threatened due to the similarity in appearance to the endangered American Crocodile • It is illegal to feed, tease, harass, molest, capture or kill alligators • The Florida Game and Fresh Water Fish Commission strictly regulate an alligator management program

40. American Crocodile

41. American Crocodile • Scientific Name and Range • Crocodylusactus Found in coastal wetlands along the Pacific Ocean from Western Mexico south to Ecuador and along the Atlantic Ocean from Guatemala north to the extreme tip of Florida

42. America CrocodileHabitat • Tropical wetlands and freshwater rivers • Mangrove-lined saltwater estuaries. Adults can survive in salt water but babies can not • Not considered a marine animal but have been found to travel hundreds of miles across the ocean to reach some isolated volcanic islands

43. Mangroves

44. American CrocodilePhysical Description • Adult crocodiles range from 7 to 30 feet long (larger than the alligator) • Snout is longer and more pointed than alligators • Fourth tooth on each side of the lower jaw is always visible. Teeth are used for seizing and holding prey not chewing. Replaced continuously (as new ones grow up, force old ones out

45. Crocodile’s Tooth or Teeth Showwhen mouth is closed

46. American CrocodileFeeding Habits • Carnivores • Feeds largely on fish and other small marine life • Larger ones may also feed on small mammals, birds and turtles • In Florida, known to eat bass, tarpon and mullet

47. American CrocodileReproduction • Male and females mate with several partners during their mating period • Females lay as many as 40 eggs. Females build mound nests of soil and sand. Some build hole nests. Eggs are warmed by the sun

48. American CrocodileReproduction

49. American CrocodileReproduction • Only 50 % of the eggs will hatch • Only 10 % of those that hatch will survive the first year

50. Crocodiles and Humans • More likely to attack than alligators (alligators will usually attack only when cornered) • More ferocious than alligators • Ancient Egyptians considered the crocodile a symbol of the Gods and it is still regarded as sacred by some groups in Pakistan • Crocodile hides have been used to make belts and handbags