Manatees are gentle, barrel-shaped aquatic mammals that gracefully navigate coastal waters, rivers, and springs. These peaceful creatures, often referred to as “sea cows,” are strict herbivores, meaning their diet consists entirely of plant material. This plant-based sustenance fuels their large frames and shapes their behaviors within their aquatic environments.
The Manatee Menu: Aquatic Plants
Manatees consume over 60 different species of aquatic vegetation found in both freshwater and saltwater habitats. In marine environments, their diet primarily includes various types of seagrasses. Preferred species in these areas include turtle grass, manatee grass, and shoal grass, along with marine algae and occasionally mangrove leaves.
In freshwater systems, manatees eat plants such as water hyacinths, water lettuce, and hydrilla. They also graze on other submerged and floating vegetation like eelgrass, coontail, pickerelweed, and musk grass. This adaptability allows manatees to thrive in diverse locations, from coastal areas to inland rivers and springs.
How Manatees Eat and How Much
Manatees have specialized adaptations for consuming their fibrous diet. They use strong, flexible front flippers to pull plants towards their mouths. Their large, prehensile upper lip is split and moves independently, helping them grasp, tear, and manipulate vegetation.
Behind their lips, manatees use horny, ridged pads on the roof of their mouth and lower jaw to break down plant material. Their molars then grind the vegetation, exhibiting a unique “marching molars” system. As front molars wear down, they fall out, and new molars continuously move forward from the back of the jaw to replace them throughout the manatee’s life.
These large herbivores consume a substantial amount of food daily, eating 10 to 15 percent of their body weight in vegetation. For an average adult manatee weighing between 800 and 1,200 pounds, this means 100 to 150 pounds of plants each day. To maintain their energy needs and large size, manatees spend approximately six to eight hours per day grazing.
The Role of Diet in Manatee Health and Conservation
A healthy and abundant supply of natural food sources is important for manatee survival and the well-being of their ecosystems. Manatees contribute to aquatic environments by grazing, which helps control vegetation growth, including invasive species like hydrilla and water hyacinth. This grazing also prevents overgrowth in seagrass beds, promoting habitat health.
Manatees face dangers when their food sources are compromised or they encounter non-food items. Ingesting debris such as plastic bags, fishing lines, or deflated balloons can obstruct their digestive systems, cause internal injuries, and lead to starvation; many manatees have ingested plastic. Feeding manatees can alter their natural behaviors, causing them to lose wariness of boats and people, which increases their risk of collision or entanglement. It is illegal to feed manatees, as it is detrimental to their long-term health and survival.