Hobbies And Interests
Algae
Algae is a single-celled plant that lives in both aquatic and land-based environments. Algae that thrive in warm salty waters tend to grow well on the backs of manatees, who spend much of their time submerged just below the surface of the shallow waters off the coast of Florida. The algae that grows on the backs of manatees does not harm them in the least, but also does not offer the manatee any benefits.
Sea Vegetables
Sea grasses, or various types of seaweed, are the main diet of manatees. These sea vegetables, as they are more correctly called, grow well in warm, shallow waters. Where sea vegetables grow, manatees are sure to follow. Sea vegetables are essential to manatees and, without them, they starve. Unfortunately, sea vegetables that manatees eat tend to grow in areas where humans ride motorized water craft, such as motorboats. Since manatees spend much of their time near the surface of the water grazing on the tips of sea vegetables, they are often hit by jet skis and the propellers of boats. While sea vegetables are essential for manatees, they can also lure them into areas where they can be harmed.
Humans
Humans are not a predator of manatees and, before the invention of motorized boats and watercraft, humans were not a biotic factor for manatees. However, as humans continue to develop the coast of Florida, flooding it with fishing and pleasure boats, they have become a biotic force to be reckoned with for the manatee. Humans now negatively effect manatees by habitat degradation and destruction through the development of coastlines and by accidentally injuring them with motorized watercraft. However, humans also positively effect manatees through conservation programs and by rehabilitating injured manatees and taking in orphaned manatee babies and raising them until they can be re-released into the wild.
Other Animals
Manatees do not have any real natural predators, though occasionally the old, young and sick are preyed upon by sharks. Since manatees are vegetarians, they do not hunt fish or other small animals. Some fish graze upon the algae that grows on the manatee's back, which can be beneficial to the manatee by keeping its back clean. Manatees can be affected by bacteria or viruses in the water. In 1996, manatees in south Florida began to die in record numbers from a certain type of pneumonia. Pathogens that affect manatees can come from a number of sources, including run-off from urban areas, sewer waste and natural factors in the environment.