Seahorses | National Geographic (2024)

Common Name:
Seahorse

Scientific Name:
Hippocampus

Type:
Fish

Diet:
Carnivore

Group Name:
Herd

Average Life Span In The Wild:
1 to 5 years

Size:
0.6 to 14 inches
Size relative to a teacup:

Seahorses | National Geographic (1)

Seahorses | National Geographic (2)

What are seahorses?

The oddly shaped and upright-swimming seahorse seems an unlikely fish. Yet more than 45 species live in coastal waters around the globe. Scientists have learned their basic biology, but much remains unknown about these charismatic animals.

Physical description

Its head may resemble a horse’s, but each seahorse has a look all its own. Most are spotted, speckled, or striped, and some are decked out in skin frills, spikes, and crowns. Colors vary and can change with the twitch of a muscle to offer camouflage or to signal a foe or potential mate.

Seahorses have flesh-covered bony plates instead of scales, eyes that work independently of each other, and prehensile tails—used to grip holdfasts on the seafloor to avoid drifting and, during courtship, to link to each other.

The tiniest species is no bigger than a lima bean; the largest can reach more than a foot from head to tail tip.

Habitat and movement

Preferring calm, shallow waters, seahorses thrive in seagrass beds, mangroves, estuaries, and coral reefs in temperate and tropical waters around the world. Relatively inept swimmers, the fish get around with frantic beats (up to 70 times per second) of a dorsal (back) fin and rely on tiny pectoral fins for stability and steering. Easily exhausted, many are swept away in heavy currents or killed in storm-roiled seas.

Diet

Seahorses are ambush predators: They hold still and wait for krill, copepods, fish larvae, and other tiny edibles to float by and then nab them with remarkable speed. Toothless and lacking a stomach for food storage, the animals use their long snouts like vacuum cleaners to suck up plankton nearly continually.

This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at @natgeoyourshot or visit us at natgeo.com/yourshot for the latest submissions and news about the community.

This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at @natgeoyourshot or visit us at natgeo.com/yourshot for the latest submissions and news about the community.

Photograph by Danny Bergeron, National Geographic Your Shot

Courtship

Seahorses are dancers at heart, circling one another or a floating object, flashing colors, and intertwining tails during a sometimes days-long courtship. Said to mate for life, a pair’s commitment may actually be fragile: If the two are separated for a time, or if the male’s health declines, a female may switch partners rather than stick with her original choice.

Reproduction

In a reproductive role reversal unique to seahorses and others in the family Syngnathidae (which also includes pipefish and sea dragons), males experience pregnancy. During mating a female uses a tube called an “ovipositor” to place her eggs into the male’s frontal “brood pouch.” He then incubates, nourishes, and carries the young to term—usually two to four weeks. With powerful contractions he’ll give birth to fully developed fry, from dozens to more than a thousand depending on the species. Newborn seahorses, set adrift, are immediately vulnerable to predators, and few survive their early days.

Threats

Pollution and coastal development harm seahorses, but the top threat is rampant overfishing. Commercial fishermen scoop up millions of seahorses a year as bycatch. There is also targeted fishing of seahorses to supply tourist demand for dried trinkets and an unregulated traditional-medicine market in Asia.

Population data for many seahorse species is sparse, but scientists believe the vast majority are threatened and some populations in rapid decline. How warming seas due to climate change will affect seahorses long term is unknown.

Saving seahorses

Protecting seahorses will require protecting their shallow-water habitats from pollution and destructive development, enforcing commercial-fishing laws aimed at stemming the bycatch problem, and reducing demand for these animals as trinkets and supposed medicinal supplements.

DID YOU KNOW?


The genus name for seahorses, Hippocampus, roughly translates from the Greek to “horse-like sea monster” or, by another translation, “horse-like caterpillar.”
UselessEtymology.com

The hippocampus in the human brain is named after the seahorse (genusHippocampus) as it resembles the fish in shape.
UselessEtymology.com

A male seahorse may carry more than a thousand embryos in his brood pouch at one time.
Zoe M. G. Skalkos, et al. Journal of Comparative Physiology B (2020)

While seahorses mostly stay put, some are known to migrate, often tucked into seaweed clumps that carry them long distances (called “rafting”).
Project Seahorse

Seahorses are marine animals—living in saltwater—but can tolerate a range of salinity levels, including the brackish waters of estuaries, where fresh and saltwaters meet.
Project Seahorse

While young are developing in the male seahorse’s pouch, he transports nourishment to them through a placenta—though exactly how it functions (there is no umbilical cord) is not yet known.
Zoe M. G. Skalkos, et al. Journal of Comparative Physiology B (2020)

Seahorses | National Geographic (2024)

FAQs

What is the geography of seahorses? ›

Seahorses are mainly found in shallow tropical and temperate salt water throughout the world, from about 45°S to 45°N. They live in sheltered areas such as seagrass beds, estuaries, coral reefs, and mangroves. Four species are found in Pacific waters from North America to South America.

Where are seahorses usually found? ›

All seahorses are marine species. They are typically found in seagrass beds, mangrove roots, and coral reefs, in shallow temperate and tropical waters. Some species can also be found in estuaries, as they are able to tolerate wide ranges in salinity.

What countries do seahorses live in? ›

Eastern Atlantic – from the UK to Angola, and throughout the Mediterranean Sea. Indian Ocean – from South Africa to Australia, throughout the Middle East, South Asia and Southeast Asia. Western Pacific – from South Korea to New Zealand and Tasmania in Australia, and some Pacific islands.

What are some facts about horses National Geographic? ›

There is only one species of domestic horse, but around 400 different breeds that specialize in everything from pulling wagons to racing. All horses are grazers. While most horses are domestic, others remain wild. Feral horses are the descendents of once-tame animals that have run free for generations.

What is the geographic range and habitat of the lined seahorse? ›

These seahorses can be found in the western Atlantic Ocean, from Nova Scotia to Uruguay. Seahorses primarily eat larval shrimp, amphipods, copepods, worms and small snails. Lined seahorses typically range from 2 to 4 inches, with a maximum size of 6 inches.

Do seahorses live in the rainforest? ›

You probably looked at my title and thought, that's not a tropical animal, when really it is. Seahorses live in coral reefs which are the rainforest of the ocean world. Presently seahorses rely greatly on the coral reefs they live by for survival, but in the future due to climate change they could lose that habitat.

Are seahorses asexual? ›

Sea horse reproduce sexually by internal fertilisation. After fertilisation female spray or transfer her eggs in the males brood pocket via oviduct and then male keep them in pocket until they hatch and are capable of fairly active swimming.

Are seahorses endangered yes or no? ›

In the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, two seahorse species are listed as Endangered, 12 as Vulnerable, with one as Near Threatened, 10 as Least Concern.

Do seahorses live in America? ›

There are currently five recognized species of seahorses (Hippocampus spp.) in the Americas, one in the Pacific Ocean and four in the Atlantic. All of these American seahorses tend to live in relatively shallow coastal areas with 3D-structured habitat, including seagrasses, corals, and mangroves.

What are baby seahorses called? ›

A baby seahorse is called a “fry.” When the time is right for the babies to be born, the males will bend their bodies back and forth until a tiny seahorse pops out of the pouch.

Are seahorses only female? ›

The most distinguishing difference between male and female seahorses is the male broodpouch located beneath his abdomen along the front side of his tail. The male's broodpouch is where the male seahorse fertilizes eggs and carries seahorse fry. You heard it right, male seahorses actually get pregnant and gives birth!

Are seahorses rare? ›

Seahorse habitats are at risk

The situation is so bad that some species, including White's seahorse (Hippocampus whitei) and the Knysna or Cape seahorse (Hippocampus capensis), are now considered endangered. This means that some of these these unique fish are now at very high risk of extinction.

What is a female horse called? ›

A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than four years old.

What is the only truly wild horse left in the world? ›

Przewalski's horses, critically endangered horses found in Mongolia, are the last truly wild horse. Once thought to be the ancestor to the domestic horse, they are actually distant cousins. Mitochondrial DNA suggests that they diverged from a common ancestor 500,000 years ago.

What is the geographic range of horses? ›

Some spread as desert-shaped onageers and asses across Asia, the Mideast, and North Africa. Others entered Africa and diversified into modern zebras. Other Equus species spread into South America while the true horse, Equus caballus, spread across Asia, the Mideast, and Europe.

Do seahorses live on land? ›

Seahorses are fish and have many of the characteristics of their swimming counterparts, according to The Seahorse Trust. They live in the water and breathe through gills. They also have a swim bladder, which is an air-filled balloon-like organ that gives them buoyancy and helps them float.

What is the natural environment of the lined seahorse? ›

The lined seahorse occurs at depths from 2-230 feet (. 5-70 m) and is often observed clinging to aquatic vegetation including mangroves, seagrasses, sponges, corals, and floating sargassum. Those that reside with sargassum often have protuberances and fleshy tabs that aid in camouflage.

How do seahorses interact with their environment? ›

Seahorses have unique adaptations that help them survive in the ocean, including the ability to use camouflage, or blend in with their surroundings, and change the color of their body. Long snouts help them find food, and excellent vision and eyes that can move independently are great for avoiding predators.

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