Everything about Whalebone totally explained
Baleen or
whalebone is the means by which
baleen whales feed. These whales don't have
teeth, but instead have rows of
baleen plates in the upper
jaw – flat, flexible plates with frayed edges, arranged in two
parallel rows, looking like
combs of thick
hair. Baleen isn't bone, but is composed of
keratin, the same substance as hair,
horn,
claws and
nails. Whales use these combs for
filter feeding. Whales are the only vertebrate group to use this method of feeding in great abundance (
flamingos and
crabeater seals use similar methods, but don't have baleen), and it has allowed them to grow to immense sizes. The
blue whale, the largest animal ever to have lived, is a baleen whale.
Depending on the species of whale, a baleen plate can be 0.5 to 3.5
m (2 to 12
ft) long, and weigh up to 90
kg (200 lb). Its hairy fringes are called baleen hair or whalebone-hair. Baleen plates are broader at the gumline (base). The plates have been compared to
sieves or
Venetian blinds.
The word "baleen" derives from
Early Modern English word meaning "
whale". This in turn derives from the
Latin balaena, related to the
Greek phallaina – both of these also mean "whale".
Evolution of baleen
The oldest true
fossils of baleen are only 15 million years old, but baleen rarely fossilizes, and scientists believe it originated considerably earlier than that. This is indicated by skull modifications which are associated with baleen (such as a buttress of bone found beneath the eyes in the upper jaw, and loose lower jaw bones at the chin), being found in fossils from considerably earlier. Currently, baleen is believed to have evolved around thirty million years ago, possibly from a creature with a hard, gummy upper jaw, similar to that found on
Dall's porpoise today, which are, at a microscopic level, almost identical to baleen.
Curiously, many early baleen whales also had teeth, but these were likely used only peripherally, or perhaps not at all (again, similar to Dall's porpoise, which catches squid and fish by gripping them against its hard upper jaw).
Baleen in filter feeding
A whale's baleen plates play the most important role in its filter feeding process. In order to feed, a baleen whale opens its mouth widely and scoops in dense
shoals of prey (such as
krill (euphausiids),
copepods or small
fish), together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey which is then swallowed.
Uses of baleen
Whalebone was formerly used in buggy whips and parasol ribs, and to stiffen parts of women's stays and
dresses, like
corsets. It was commonly used to crease
paper; its flexibility keeps it from damaging the paper. Its function now has been replaced by
plastic.
Further Information
Get more info on 'Whalebone'.
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