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350
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© Andrew Young
The mole-rat, here from Damaraland, an exotic animal model
Kalahari Desert
(South of Africa)
© Dmitry Pichugin - Fotolia
© massimhokuto - Fotolia
lamp. The currently mainstream biological
model systems sure shine a powerful light, but
the keys to some really interesting (and important)
questions may simply not be found under it
.” However, we
thought that the naked mole-rat was preserved from cancer, but tumours
have just been discovered in animals kept in American zoos. It will obviously be very interesting to
determine what elements led these animals to develop tumours, in order to possibly learn lessons for
human health.
Research on mole-rats is conducted in the laboratory, but mechanisms developed by some exotic animals
may only be studied in nature. Thus, one of the most remarkable model animals
is the hibernating bear. Echocardiography performed on the bear
show that its heart beats about 60 beats per minute - a
rate that reduces to 5 or 6 beats per minute when
the bear hibernates. What is extraordinary
in this hibernation fasting is that the bear
exclusively uses its own fat: it saves its
muscles and all its other valuable body
proteins, which explains why it does not
urinate or defecate for the 5 to 6 months
of its hibernation. Bears are among the
only animals able to do so: men, as any
other animals, with a few exceptions such
as some bats, experience a reduction of
their muscle mass when they fast. Indeed,
in the treatment of severe obesity, even when
there is still a lot of excess fat, very low calorie