CHATTANOOGA, Tenn. (Feb. 21, 2002)
- Mythical, marvelous and amazing - no matter what word
is used to describe them, seahorses capture the imagination
as some of the sea's most unusual inhabitants. But one of
the most fascinating features of seahorse behavior is the
way they woo and then brood.
It all begins
with a slow, dance-like promenade through the sea grass.
The male, head bowed, performs an elaborate dance around
the female, often wrapping his tail around her or mimicking
her movements. The male often changes color, his body becoming
lighter while his spine area darkens. During this mysterious
mating dance, the male opens his empty pouch to the female.
If the female is satisfied, she raises her head and intertwines
her tail with his.
can last up to nine hours and resembles a sort of ballet,"
said Thom Demas, Tennessee Aquarium senior aquarist. "The
seahorse pair travel up the water column as she transfers
eggs to the male seahorse's pouch on his abdomen, where
he fertilizes the eggs and goes through the pregnancy."
In all species
in the family Syngnathide - seahorses, seadragons
and pipefish - it is the male who carries and nurtures the
eggs. In the case of seahorses, the male actually becomes
pregnant. Each fertilized egg embeds into the lining of
his pouch, where tissue grows around the eggs and supplies
them with oxygen throughout the pregnancy. This tissue does
not supply nutrients to the eggs; the main source of nutrition
is in the yolk of the egg itself.
The male seahorse
carries the eggs for a period of 10 to 30 days, depending
on the species and water temperature. The babies, which
can number between 10 and 500 depending on the species,
emerge as tiny replicas of the adults, ready to begin life
on their own.
Most seahorse pairs are monogamous - once a male and female
form a pair bond, they mate exclusively during the breeding
have a different style of breeding. With the approach of
warmer weather, male and female seadragons form pairs. Once
paired, both seadragons keep close together, never floating
too far away from their mate. The female seadragon develops
up to 300 orange eggs within her lower abdominal cavity.
During this period, the male goes through some of his own
interesting transformations. As the eggs are developing
in the female, the tail of the male enlarges and becomes
wrinkled and a network of fine blood vessels develops. Once
the tail is fully enlarged, approximately 120 small pits,
or eggcups, appear in preparation to receive the eggs. The
female then deposits the eggs into the cups, and the male
It takes weeks
for these transformations to occur, and during that time
the male seadragon can be seen displaying to the female.
He swims alongside her in a distinct head-up-head-down motion.
Sometimes the female returns a similar motion to the male.
Occasionally, the male approaches the female from the front,
turning his body upside down, possibly showing off his readiness
to reproduce. He also becomes extremely aggressive during
this period, chasing away any potential predators from the
female. When the egg transfer occurs, the female floats
upward in an exhaustive state.
have interesting mating characteristics. Like seahorses
and seadragons, the male is the primary carrier of eggs,
but in some species, the female carries them. In contrast
to seahorses and seadragons, pipefish are not "monogamous."
The female leaves her eggs with several different males,
and males may carry the eggs of several females at one time.
In most cases, the carrier pipefish attaches the eggs to
the underside of the belly, where they are fertilized and
incubated. Certain species, such as the banded pipefish,
dance with one another during this courtship. They snake
between one another, often bending their bodies in the shape
of a half circle or a cross. From time to time, both move
their heads simultaneously in a special rhythmic bob. Once
the dance is finished either the male or female swims off,
with eggs attached to its abdomen.
the young hatch, their parents play no role in their upbringing.
Very few young seahorses survive to adulthood, falling to
predators, swept away by ocean currents or harvested by
humans for a variety of uses.