Manatees, often called “sea cows,” are large, gentle aquatic mammals found in warm coastal waters. These herbivores are known for their slow, peaceful movements and their grazing on seagrass and other aquatic plants. The lifespan of a manatee can vary significantly, with individuals in their natural habitat generally living shorter lives than those under human care.
Lifespan in Different Environments
Manatees in the wild have the potential to live for 50 to 60 years. In contrast, manatees in human care often live longer, frequently surpassing 65 years. For instance, Snooty, a well-known manatee, lived to be 69 years old in a controlled environment.
This difference in longevity is largely due to the consistent food supply, protection from predators, and regular veterinary attention provided in captive settings. Scientists estimate manatee age by examining growth layers in their ear bones, similar to counting tree rings. While this method is precise for deceased individuals, age estimation for living manatees relies on size classification and known birth dates, if available.
Influences on Manatee Longevity
Manatee longevity is shaped by a combination of natural and human-related factors. Natural causes of death include predation by sharks, alligators, or crocodiles on calves. Manatees are also vulnerable to cold stress, particularly when water temperatures drop below 68 degrees Fahrenheit, which can lead to illness or death. Additionally, natural phenomena such as red tide blooms produce toxins that can be fatal if ingested or inhaled. Diseases and parasites also contribute to natural mortality.
Human activities are a primary cause of manatee mortality. Collisions with watercraft, including propeller cuts and hull impacts, are a leading cause of death for these slow-moving animals. Habitat loss and degradation, especially the destruction of seagrass beds which are their primary food source, lead to starvation and poor health. Manatees can also become entangled in fishing gear such as lines and nets, resulting in injuries, infections, or drowning. Furthermore, entrapment and crushing in floodgates and canal locks pose a risk, as does the ingestion of plastic and other debris.
Conservation and a Longer Lifespan
Conservation efforts are underway to protect manatees. Establishing and enforcing regulatory speed zones for boats in manatee habitats helps reduce the risk of collisions. Habitat restoration projects, such as planting seagrass and protecting warm water springs, are improving their access to food and shelter.
Rescue and rehabilitation programs are crucial for manatees that are injured or sick. Organizations like the Manatee Rescue & Rehabilitation Partnership work to provide medical care, with the aim of returning healthy manatees to their natural environment. Public awareness campaigns educate boaters and the general public about responsible interactions with manatees. Legal protections, including the Marine Mammal Protection Act, the Endangered Species Act, and the Florida Manatee Sanctuary Act, provide a framework for their safety. Ongoing research and monitoring continue to inform these conservation strategies.