Dads at the Tennessee Aquarium
Seahorses take fatherhood to a whole new level
Tenn. (May 27, 2003) - Forget about those modern dads who change
diapers or get up for midnight feedings. Seahorse dads take parenting
to a whole new level - they actually go through pregnancy and
may sound like science fiction (or the basis for a bad comedy),
but males undergoing pregnancy is a fact of life for seahorses.
it is strange and as far as we know, seahorses are the only species
in which the males actually undergo pregnancy,” said Thom
Demas, Tennessee Aquarium Curator of Fishes.
along with aquarists Shelly Scott and Natalie Fisher, care for
the hundreds of seahorses at the Aquarium. Although they spend
a great deal of time observing these mysterious sea creatures,
no one really knows why it is the seahorse dads, and not the moms,
who carry the children.
are theories,” Demas said. “But there’s not
much research regarding seahorses. Many aspects of their lives
remain a mystery.”
recent studies have allowed researchers to learn a lot about seahorse
courtship, mating and reproduction. It all begins with a slow,
dance-like promenade through the sea grass. With his head bowed,
the male seahorse 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, he
opens his empty pouch to the female. The female then raises her
head and intertwines her tail with his.
ritual can last up to nine hours and resembles a ballet,”
Demas said. “The seahorse pair travels up the water column
as the female transfers eggs to the male seahorse’s pouch
on his abdomen, where he fertilizes the eggs and goes through
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 egg yolk.
many fish species, both male and female provide parental care,
Demas explained. Usually this involves guarding the eggs from
potential predators and fanning the eggs to make sure they get
enough oxygen and stay clean, he said. Seahorses are the most
extreme example of fathers providing care. They provide oxygen
through a capillary network in the pouch, transfer nutrients,
and control the pouch environment so that it changes during the
pregnancy to become more like salt water.
male seahorse carries the eggs for 10 to 30 days, depending on
the species and water temperature. The babies, which may number
more than 1,500 depending on the species, emerge as tiny replicas
of the adults, ready to begin life on their own.
seahorse pairs are monogamous - once a male and female form a
pair bond, they mate exclusively during the breeding season. Again,
scientists aren’t sure why they pair bond, and monogamy
is unusual in the animal word. However, some theorize that seahorse
pairs that stay together get better and better at raising offspring.
think it’s a case of practice makes perfect,” Demas
leads to another unusual aspect of seahorse reproduction: males
usually get pregnant again immediately after giving birth!
an egg transfer will take place with a few minutes of the male
giving birth,” he said. “Sometimes they wait a little
longer, but the males are almost always pregnant again within
24 hours of giving birth.”
Tennessee Aquarium inspires wonder and appreciation for the natural
world. Admission is $14 per adult and $7.50 per child, ages 3-12.
Each ticket purchased helps support Aquarium conservation programs.
The IMAX® 3D Theater is next door to the Aquarium. Ticket
prices are $7.75 per adult and $5.25 per child. Aquarium/IMAX
combo tickets are $18 for adults and $10.50 for children. Advance
tickets may be purchased online at www.tnaqua.org or by phone
at 1-800-262-0695. The Aquarium, located on the banks of the Tennessee
River in Chattanooga, is a non-profit organization. Open every
day except Thanksgiving and Christmas, the Aquarium and IMAX are
accessible to people with disabilities. Members enjoy unlimited
visits and other benefits. Call 267-FISH to join.