Horn Shells - Family Cerithiidae

Above : Clypeomorus coralium, Coral horn shell, 25 mm.

Below left : Cerithium echinatum, Spiny horn shell, 42 mm.

Below center : Pseudovertagus aluco, Aluco horn shell, 57 mm.

Below right : Rhinoclavis sinensis, Obelisk horn shell, 46 mm.

 

Horn shells are a large group characterized by an upturned canal in their shell that protects the siphon and allows them to live just beneath the surface of the sand. They are some of the most commonly-seen and abundant seashells in shallow water. At shallow depths the smaller species prefer to live in sand pockets and calm, protected bays, while the larger species are normally found in open sand beyond the reef.

These shallow-water dwellers can best be seen in the early morning before wind-driven waves and tides obliterate the trails left in the sand from the evening's foraging. The trails of deeper-water dwellers can be found throughout the day.

All are algae and detritus feeders and are common prey for predatory mollusks, especially moon shells which drill a hole through the shell and extract the animal. Hundreds of drilled horn shells, occupied by hermit crabs, can sometimes be seen on the reef flat at low tide.

Authority : Tropical Seashells of Indonesia

Manatees

Some early explorers spied manatees with seaweed draped over their bodies and mistook them for mermaids. But in reality, these gentle giants looks more like sumo wrestlers than mermaids. Sometimes called sea cows, full-grown manatees weigh in at a whopping 800 to 1.300 pounds (362 to 589 kg) and can eat as much as a tenth of their own weight in sea grasses and other plants every day.

Flicking their strong, paddle-shaped tails, manatees glide along at a leisurely five miles an hour (8 kph) so slowly that algae can actually cling to their soft, wrinkly skin. But these marine

mammals can ratchet up to 20 miles an hour (32 kph) when necessary. Living in warm, shallow waters, manatees use their front flippers to steer, sticking their lumpy snouts above the water's surface every 10 to 25 minutes to gulp air.

A mama manatess gives birth underwater and helps her baby to the surface for its first breath. Within minutes, the three-foot-long (91 cm) baby will start swimming but will stick with mom, nursing on her milk for the first year of its life.

A Manatee's Heaven

Mangroves are an ideal rest stop for manatees and a home to many other animals. A jumble of skinny roots and low-hanging branches, mangrove trees (below) thrive in estuaries, where freshwater and saltwater mix.

Oysters and barnacles anchor themselves to the threes' dense roots, helping to filter water and trap nutrients in the woody stems. The result is a nutrient-packed nursery for young fish, sharks, crustaceans, and shellfish. Mangroves also provide nesting and hunting areas for seabirds. Keeping mangroves helping is an important part of protecting ocean animals.