Home Sweet Corral (Eh, Coral, That Is)
Seahorses are found all over the world. Although they tend to prefer shallow, warm tropical waters, there are also a few cold-water species. Their habitats range from oceans as far north as Norway and New Zealand in the Southern Hemisphere. They are typically found in coral reefs or tethered to sea grass.
A common species, the five-inch (or 19 cm) long Mustang has the Latin name Hippocampus erectus—meaning, Horse fish with upright stature—and we can’t forget the popular dwarf variety, the Hippocampus zosterae, the most popular of all marine fishes. They can be as small as a peanut to as large as a banana. Scientists surmise there are between 47 and 53 different kinds of species.
Seahorses can be noisy little guys, known to make a smacking noise through their aardvark-like snouts. Divers can attest to this, because it happens frequently during feeding and courtship.
They don’t have teeth but rather suck up through their schnozzles delicacies, such as plankton, shrimp, krill or small crustaceans. At the other end, they have no stomach. The nutrients in their food pass through their little bodies quickly, making them constant grazers that eat nearly all the time, taking in miniscule food whole like a vacuum.
Terrible swimmers, seahorses often attach themselves to objects such as floating debris or seaweed and travel long distances. The appearance of their body armor is like interlocking bony plates that form ridged rings that often resemble bolts—they are all knobs and spines—with an exoskeleton that is made up of hard, outside shields.
They also have a trait generally given over to monkeys—a prehensile tail that acts like an anchor grabbing onto objects (especially during storms) because they are poor aquanauts.
Why? It is because they only have a transparent dorsal, or back fin, which oscillates as fast as 20 to 30 times per second, but creates only slight ripples through the water. Their pectoral or chest fin acts as a rudder, somewhat like a helicopter shaft as it balances with its tail, which the seahorse can use as a directional.
Speaking of that tail, when seahorses want to descend, they curl their tails and to rise to the surface, they straighten them.
Now You See Me, Now You Don’t
Because they are such poor swimmers, they have some ingenious features that protect them from predators. First, they are generally mottled in appearance and can be white, tan, brown, yellow, green or gold. The really magical thing is that they can expand or contract their tiny pigment cells—called chromatophores—changing the color of their skin to help camouflage themselves. They often look like the background, whether that is bright-colored coral, green grass or speckled stone.
Many also have dermal cirri—spine-like spikes that make them look either a little shaggy or knob-hard spindly. Their tough, bony skin helps them to not be eaten unless their attacker wants a crunchy meal.
With more strangeness to boot, they do have an eye on the matter because their bulging, lizard-like eyes can operate independently. This means they are able to look around in many directions. This neat trick allows them to eat and watch out for predators simultaneously.
Pregnant Shorthead Seahorse
Most wild seahorses are monogamous and some species mate for life. In addition, they are among the only animal species where the male bears the young.
First, there is a kind of mating ritual where the female and male seahorse do a type of pas de deux—French for, “a dance for two." The female seahorse entices the male into coming forth. Both wrap their prehensile tails around blades of grass and they sway.
They repeat this dance for a couple days. While they circle each other, their color may change from brown to green. When the waltz is over, they entwine their tails. The male has a kangaroo-like pouch that fills with seawater. The female deposits hundreds of eggs from her body into a special tube of his. A few may be lost to the sea, but 100 to 200 eggs arrive safely.
The gestation period is two to five weeks and they feed and sway as a couple. His pouch nourishes, enfolds and protects the developing eggs. (See the photo of a pregnant shorthead seahorse.) When the eggs are ready to hatch, he pumps his tail and out they come out, fully formed and very tiny seahorses. As many as 1500 babies burst into the water, ready to begin life without any other intervention.
The Long Goodbye
This beautiful and intriguing sea life specimen is unfortunately at risk for extinction. According to The International Union for Conservation of Nature (IUCN) the Red List of Threatened Species includes 38 seahorse species; 26 are listed as “data deficient" ( meaning there is insufficient information to assess their status), 10 as “vulnerable," one as “definitely endangered" and one as being of “least concern."
Several groups are diminishing the seahorse herds so that there are only half as many as there once were. The seahorse is popular in traditional Asian medicine and about 45 tons were used for this purpose in 1996. The seahorse carcasses are dried, crushed, baked, powered and more, in order to use them in concoctions for a host of ailments from baldness to goiters and wounds.
The tourist or curio trade takes them from the wild where they are marketed as souvenirs—a hollow dried up reminder of what once was a remarkable marine life.
The pet trade also contributes to horribly high numbers of illegal transactions where they wind up for people’s personal use in home fish tanks. The numbers that survive in this manner by amateur fish enthusiasts are abysmal.
In addition, their ocean habitat, the coral reefs, have diminished greatly over time. Coastal development, dredging, destructive fishing practices and incidents such as oil spills all contribute to their demise and an inability for the seahorse to adapt and live.
- Ocean Portal: 10 Things You Never Knew about Seahorses
- Image: Courtesy of Copyright Rob & Sue Peatling 2014
- AWI Online: Extinction
- Seahorse.org: Seahorse Anatomy Drawings
- Curtis, Jennifer Keats. Seahorses. New York: Henry Holt and Company. 2010. Book.
- The Guardian: BP Oil Spill Endangers Seahorses
- Fused Jaw: Conservation Resources
- National Geographic: Map of the Seahorse Range
- Wearing, Judy. Seahorses. New York: Weigl Publishers, Inc. 2010. Book.
- Giwojna, Peter. A Step-By-Step Book about Seahorses. Neptune City, NJ: T.F.H. Publications, Inc., 1990. Book.
- Animal Diversity Web: Hippocampus Erectus