How can you tell a hagfish if you
look kind of like eels or lamprey, being long, slender and light
pinkish grey in colour.
are elegantly simple in design, having no fins (except for
a primitive tail fin), knobby protrusions, and few accessories
to speak of.
eyes are reduced but they have good senses of touch and smell.
have a ring of short sensitive tentacles around their mouths.
slime glands line their sides along the length of their bodies.
What do they do?
a long time, people thought of hagfish as scavengers and parasites,
probably due to their habit or burrowing into dead or dying animals
and eating them from the inside out. In fact, most of their diet
is made up of marine worms and other invertebrates. Scientists
used to think the hagfish looked primitive as a result of the
loss of characteristics often associated with being a parasite.
Now common belief is that hagfish just haven't needed to change
for the last couple of hundred million years. Now that's a successful
body plan and lifestyle!
ability that had won fame for hagfish is the mass amounts of
slime almost instantly secreted as a defense mechanism.
Where are they found?
can be found in the chilly waters of the antitropical north and
tend to live on and in muddy sea floors in very dense groups
(up to 15,000 in an area). Because females tend to produce
large eggs in small numbers, their population sizes suggest
a low death rate.
What kind of tricks can they do?
very useful trick hagfish have developed is the ability to tie
themselves in knots, and be able to slide in and out of this
knot. This can be used to escape predators, to clean themselves
of slime, and to work their way into a carcass. This picture
shows: A) knotting; this movement is used to clean slime off
the body; B) escaping from capture using knotting, a very powerful
motion; C) pulling on food by knotting
can also sneeze to unclog their nostrils of their own slime.
What else makes them special?
don't really have jaws. Instead they have two pairs of rasps
on top of a tongue. They pull meat into their mouths with the
tongue, then tear it off the prey with the rasps.
hatched hagfish look just like the adults, but have both male
and female sex organs. When they mature, they will be either
male or female, but have the ability to change from one to
the other if the population structure demands it.
have a very low metabolism. Once they eat, they may not have
to again for up to seven months.
hagfish have a partial skull, they have no back bone, so are
not true vertebrates. What skeleton they do have is made of
How are they used by people?
Yes, humans will find a way to exploit
even these seemingly useless and repulsive animals.
Korea, almost 5 million pounds of hagfish meat are consumed each
skin is processed into "eelskin" boots, bags, wallets,
purses, and other products.
in Asia has decimated their local hagfish stocks, so the Asian
hagfish fishery has turned its eyes towards North America,
where these "slime eels" are considered a worthless
could mean a boost of over $2 million to the local fisheries,
but care must be taken not to damage these stocks as well.
Hagfish may not be pretty in most people's eyes, but they serve
a purpose and are slow to reproduce. It would take them a long
time to recover from over-harvesting. Who can tell what removing
them from the local food web would do?
Phylogenetics amongst species (for
hard core scientists):
There are about 20 species of hagfish
divided into four genera (Myxine, Neomyxine, Paramyxine,
and Eptatretus). These four groups make a sort of evolutionary
continuum with regards to external traits. For example, the Myxine and Neomyxine are
considered more advanced than the latter two for several reasons:
have a single pair of common external gill openings. The latter
two have two minute separate gill openings (considered primitive). Paramyxine's
openings are closer together than Eptatretus' so Paramyxine is
considered more closely related to the first two.
eyes in Myxine and Neomyxine are smaller than
those of the other two, suggesting a less primitive condition
by an adaptation to the dark environment favoured my hagfish.
A. and Ragnar Fange eds, 1963. The Biology of Myxine. Grondahl & Son,
Introduction to the Myxini
Journal of Young Investigators - Hagfish article
Monterey Bay Aquarium - Hagfish video!
to marine biodiversity index