Manatees and seals may seem like distant cousins when observing them in their natural habitats, but a deeper look reveals surprising similarities between these aquatic mammals. If you’re short on time, here’s a quick answer to your question: manatees and seals are related in that they’re both marine mammals, but they belong to different taxonomic orders.

Manatees are part of the order Sirenia while true seals belong to the order Carnivora.

In this comprehensive article, we’ll explore the evolutionary history, anatomical traits, and ecological niches of manatees and seals. Discover how convergent evolution has shaped these unique creatures to thrive in marine environments.

We’ll also highlight key differences that place manatees and seals in separate mammalian orders.

Taxonomic Classification of Manatees and Seals

The Order Sirenia

Manatees belong to the order Sirenia, which includes oceanic aquatic mammals such as dugongs and the now extinct Steller’s sea cow. The name “Sirenia” comes from the mythological sirens or mermaids, as early European explorers thought manatees and dugongs were mermaids.

There are only four living species of Sirenians today – the Amazonian manatee, the West Indian manatee, the West African manatee, and the dugong. All four species live in warm shallow coastal marine waters and rivers, and feed on aquatic plants.

Sirenians are large, slow-moving gentle herbivores that have evolved fully aquatic lifestyles, with flipper-like forelimbs, no hind limbs, and a horizontally flattened tail for swimming. Their bodies are fusiform and streamlined for efficient aquatic locomotion.

Sirenians have relatively low metabolic rates compared to similar-sized land mammals, which allows them to survive on a diet of low-energy aquatic vegetation. Overall, the order Sirenia represents a highly specialized and unique branch of aquatic mammals.

The Order Carnivora

In contrast, seals belong to the order Carnivora, which includes land-dwelling carnivorous mammals like dogs, cats, bears, and weasels as well as other marine carnivores like sea lions and walruses. There are 33 species of true seals, also called earless seals or phocids.

True seals are semi-aquatic, spending time both in the water and on land. They have streamlined torpedo-shaped bodies and flippers for efficient swimming. Their limbs are modified into flippers, with small clawless digits.

Seals are predators that feed on fish, crustaceans, cephalopods, and other marine creatures. They have sharp teeth and strong jaws adapted for grabbing slippery prey and tearing flesh. Seals have high metabolic rates to support an active predatory lifestyle.

Overall, the order Carnivora represents a group of nimble predators well-adapted for hunting and feeding on other animals.

Differences Between the Orders

While manatees and seals share a semi-aquatic lifestyle, they belong to completely different mammalian orders that diverged evolutionarily over 60 million years ago. Here is a comparison of some of the key differences between Sirenians and Carnivorans:

Sirenians (Manatees) Carnivorans (Seals)
Herbivores that eat aquatic plants Carnivores that eat fish, squid, crustaceans etc.
Low basal metabolic rate High basal metabolic rate
No hind limbs, only forelimbs modified into flippers All four limbs modified into flippers with digits
No claws on flippers Claws on flippers
Flattened tail for propulsion No flattened tail, use hind flippers for propulsion
Largely only found in warm waters Found in both cold and warm waters
Give birth to live young Most seals give birth on land to live young

Evolutionary Origins and History

When Manatees and Seals Diverged

Manatees and seals share a common ancestor from around 60 million years ago. At that time, the evolutionary lines of these marine mammals began to diverge as they adapted to different ecological niches.

The ancient ancestors of manatees were herbivores that lived in tropical, shallow coastal waters and estuaries. In contrast, the ancestors of seals evolved as carnivores that could thrive in colder oceans and on pack ice.

As the continental plates drifted apart over millions of years, populations became isolated and were subjected to different environmental pressures. This drove the evolutionary divergence between manatees and seals.

Manatees remained in tropical waters, while ancestral seals adapted to colder climates. Key differences emerged in their anatomy, physiology, behavior and ecology.

Environmental Pressures and Adaptations

Manatees faced the pressures of finding sufficient food in warm, shallow waters and defending against predators. They evolved to be slow-moving grazing herbivores with tough skin, a large body size, and a flat tail for propulsion. Manatees can eat up to 150 pounds of aquatic vegetation per day!

In contrast, seals adapted to chase down prey in cold Arctic and Antarctic waters. They evolved sleek, torpedo-shaped bodies, flippers for swimming, and blubber to retain heat. Some species, like leopard and crabeater seals, developed specially adapted teeth for catching fish and krill.

Other true seals, like harp and Weddell seals, evolved to hunt in deep waters, withstand freezing temperatures, and rest on ice flows.

While manatees and seals took different evolutionary paths 60 million years ago, they still share similarities as marine mammals dependent on the ocean. Hopefully, greater awareness and conservation efforts can protect these unique creatures for millions of years to come.

Anatomy and Physiology

Body Size and Shape

Manatees and seals have similar streamlined body shapes that are well-adapted for an aquatic lifestyle, but there are some key differences. On average, manatees are much larger, with adult Florida manatees reaching up to 13 feet long and weighing up to 1,300 pounds.

In contrast, true seals rarely exceed 9 feet in length and weigh over 700 pounds.


Both manatees and seals have forelimbs that have evolved into flippers to propel them smoothly through the water. However, the skeletal structure of their flippers differs significantly. Manatees have flippers with a flexible shoulder joint and individual finger bones similar to land mammals.

Seals have stiff flippers with no elbow or wrist joints, better suited for swimming.

Skeletal Adaptations

Manatees and seals have skeletal adaptations for an aquatic life, but seals’ skeletons are more specialized. For example, seals have hindlimbs stretched out horizontally to streamline them for swimming rapidly.

Manatees move much more slowly and have hip and leg bones similar in structure to land mammals.

Adaptation Manatees Seals
Vertebrae Less flexible More flexible
Ribs Thick, heavy ribs Flattened ribs

Diet and Digestive Systems

Manatees are grazing herbivores that eat aquatic plants, while seals are carnivorous marine mammals that feed on fish, squid, and other prey. Their digestive systems reflect their very different diets.

For example, manatees have Hindgut fermentation chambers and seals have a simple stomach suited for digesting meat.

Ecology and Behavior

Habitat Preferences

Manatees inhabit both saltwater and freshwater environments in coastal areas and rivers. They prefer warm, shallow waters with abundant aquatic vegetation. Common habitats include coastal tidal rivers, bays, lagoons, mangroves, and seagrass beds (1).

During cold winter periods, manatees often congregate near warm water outflows from power plants or natural springs (2). This allows them to survive in colder areas.

Social Structures

Manatees lead mostly solitary lives, but they do form temporary groups and long-term bonds. Mothers stay with their calves for up to two years. Adult males aggregate with females during mating season. Outside of mating, manatees may huddle in groups of up to a dozen animals near warm water refuges in winter (3).

These seasonal social bonds reinforce cooperation and information sharing among manatees.


Female manatees typically start breeding around 5-9 years of age, when they reach sexual maturity (4). Gestation lasts about 12-14 months. Calves nurse for up to 2 years, forming a strong maternal bond. Manatees may only birth one calf every 2-5 years due to their long parental investment.

The slow reproduction rate contributes to their endangered status.

Here is a comparison of key facts about manatee reproduction:

Average Age of Sexual Maturity 5-9 years
Gestation Period 12-14 months
Time with Mother Up to 2 years
Birth Interval 2-5 years

The long parental care and infrequent breeding reinforce the need for greater habitat protections to support the recovery of manatee populations (5). Their survival depends on suitable warm water refuges and restoration of seagrass feeding grounds along migration routes.






Conservation Status and Threats

Endangered Species Protection

Manatees have been listed as an endangered species under the Endangered Species Act since 1973, providing them with protection and conservation support. Their numbers at that time were incredibly low, with only several hundred Florida manatees remaining.

Thanks to conservation efforts their population has grown to over 6,000 today, demonstrating the success of species protection policies.

Climate Change Impacts

Climate change poses substantial threats to manatees’ future. Rising water temperatures can cause the seagrass they rely on for food to die off. Additionally, severe storms which climate change may worsen can demolish the warm-water winter refuges they depend on.

Conservationists are working to identify robust winter habitat sites to protect in preparation for future changes.

Other Anthropogenic Threats

The greatest threats to manatees come from human activity. Boat strikes account for over 20% of total deaths, as the large mammals can be difficult to spot and avoid in the waterways they share with boats. Construction near seagrass beds also severely impacts their food supply.

Conservation groups advocate for no-wake zones, recreational boating speed limits, and habitat protection regulations to mitigate these dangers.

While captive breeding programs have had little success, manatee rehabilitation centers allow conservationists to rescue, rehabilitate, and release stranded manatees. Public education is also key – teaching people how to coexist with manatees and avoid disrupting their habitats makes a big difference in preserving wild populations.

With ongoing species protection policies, habitat conservation efforts, rescue/rehabilitation programs, and public education, it is hoped the manatee population will continue to grow despite climate change and human activity impacts.

But they remain a vulnerable species requiring substantial conservation support and stewardship.


U.S. Fish & Wildlife Service – Florida manatee conservation overview
World Wildlife Fund – Florida manatee protection overview


While manatees and seals have some superficial similarities like their aquatic lifestyles and use of flippers, they belong to completely different taxonomic orders. Manatees are more closely related to elephants, while seals share ancestry with dogs, bears, and other carnivoran mammals.

Still, studying the evolutionary convergence between Sirenians like manatees and Pinnipeds like seals provides fascinating insights into how adaptation allows mammals to thrive in marine environments.

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