It is not usual to class these two families together, but they look so
much alike until studied closely, all the different varieties having the
appearance of serpents, with fins and curious forms of tails and heads,
that it seems best to study them together and find the points of
difference. The Lamprey is of a lighter color than the Eel, and is not
so graceful, but of a rather clumsy form. But it differs most in its
mouth, which is round, and placed below the end of the nose. It
resembles the mouth of a Leech more than that of an Eel.
The Lamprey has a hole on top of its head through which it spouts water,
somewhat like a Whale, and the fins are formed by a lengthening out of
the skin instead of having a set of bones or spines for that purpose.
The mouth of the Lamprey is not only formed like that of the Leech, but
it has the same property of sticking close to and sucking any body that
is applied to it. It has a wonderful power of holding on to stones by
sucking with its mouth, so that it is almost impossible to draw it away.
We are told of one that weighed only three pounds, and yet it stuck so
firmly to a stone weighing twelve pounds, that it remained suspended by
its mouth, and it was almost impossible to make it loosen its hold.
This wonderful strength of suction is supposed to arise from the power
of the Lamprey to exhaust the air within its body by the hole over the
nose, while the mouth is closely fixed to the object, and allows no air
to enter.
This adhesive or sticking quality in the Lamprey is somewhat increased
by the slimy substance which is smeared all over its body. This
substance serves to keep it warm in the cold water, and it also keeps
its skin soft and pliant.
Every year, usually about the beginning of the spring, the Lampreys
leave the sea, where they usually make their home, and make holes or
nests in the gravelly bottoms of rivers. Here the eggs are laid, and the
mother Lamprey watches near until the eggs hatch. Then she is often seen
with her whole family playing about her until they have become well
grown, when she takes the whole family back in triumph to the ocean.
There are several different species belonging to the Lamprey family. The
kind known as the Lesser Lamprey inhabits Europe, Japan and the lakes of
South America. It measures from twelve to fifteen inches long. Then
there is a still smaller member of the family called the Lampern, which
lives in European rivers, and is about six or seven inches long. It
hides itself under stones or in the mud, but does not have the same
power of suction as some of the larger ones.
The Sea Lamprey belongs to the Mediterranean. When full grown it is
about three feet long, and its light yellow body is marbled with brown.
The Lampreys feed on worms, molluscs and small Fishes. The larger ones
often seize Fishes of great size, and suck them like a Leech.
All the different kinds of Lampreys are considered very fine and
delicate food, and horrible stories are told of how kings and emperors
used to raise the best kinds of Lampreys in ponds and feed them by
throwing into the ponds live slaves who had displeased them; as they
considered the Lamprey had a finer flavor when fed on human flesh. But
only one man, a senator of Rome, was really known to do such a dreadful
thing, and we are told that when Augustus, the emperor, heard it he
ordered all these ponds to be filled up; but not until after many poor
slaves had met this awful death, simply because they did not happen to
please their wicked master.