BRUNSWICK — Manatees have returned to coastal Georgia, which means the Georgia Department of Natural Resources is again reminding boaters to be on the lookout to avoid collisions with the endangered animals.

With an estimated population of only 3,000 animals in U.S. waters, manatees, also known as sea cows, are protected as an endangered species under federal and Georgia law. Approximately one quarter of all manatee mortalities in Georgia since 1980 were caused by boat and ship collisions. Four manatees were killed last year after a ship collided with the group in the Savannah River, an incident that made headlines throughout the Southeast. Other dangers to the species include entanglement in fishing gear and harmful algal blooms known as red tides.

Although West Indian or Florida manatees are present throughout the year in warm waters off the Florida coast, they are most commonly seen in Georgia during May through September when the slow-moving aquatic mammals venture northward into Georgia’s coastal waters and farther up the east coast. They can be found in all of Georgia’s tidal rivers, estuaries and near-shore marine waters, and are most common in waters to the east of Interstate 95.

Adult manatees are approximately 10 feet long and weigh up to 1 ton.

Their skin varies from gray to brown, and their bodies are rounded with two pectoral flippers and a wide, flat tail. Subsisting on marsh grass and other aquatic plants, the animals are gentle and pose no threat to humans. It is illegal to hunt, play with or harass manatees.

Manatees have a slow reproductive rate. Females are not sexually mature until about 5 years old, and males mature at approximately 9. On average, an adult female gives birth to one calf every two to five years, and twins are rare. The gestation period is about a year.

Mothers nurse their young for one to two years, so a calf may remain dependent on its mother during that time.

The number of manatees along Georgia’s coastline each year is unknown because the turbid, murky waters near the coast make surveys difficult.

Georgia residents can help biologists learn more about the movements and habitat use of manatees by reporting any sightings and taking photographs.

Collisions between boaters and manatees are more likely to occur in shallow waters, particularly around docks and at the edge of marshes where manatees feed. Following boater safety regulations in these areas can reduce the risk of a collision. Boaters should also watch for manatee backs, tails, snouts and "footprints" — a series of round swirls on the surface caused by a swimming manatee’s tail.

If a boat accidentally collides with a manatee, the DNR Wildlife Resources Division asks that the boater stand-by and immediately contact the U.S. Coast Guard on VHF Channel 16 or DNR at (800) 2-SAVE-ME (800-272-8363). Doing so provides biologists the best chance to help the animal and gather valuable scientific data.