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According to electroencephalograph recordings of sleep states in animals,
it is possible to believe that some animals dream. REM
sleep, the "dreaming sleep," has been reported in most studied
mammals, including rats, cats, monkeys, opossums, elephants, and also
in birds. Among mammals, only the echidna does not present REM sleep.
Because REM sleep is recognizable in mammals and birds but not in snakes
and other reptiles, REM sleep may be a later phylogenetic process related
to warm-blooded animals. REM sleep appears about once in every 90 minutes
in human beings, and about once in every 25 minutes in cats. Each episode
lasts for several minutes.(fromSilvia Helena Cardoso,State
University of Campinas, Brazil <http://www.epub.org.br/cm/n02/mente/animais_i.htm>)
Comparative
percentages of total waking and rapid eyes movement (REM) sleep in some
animals.
| Subjet
|
Waking |
REM |
| Cat |
42.3 |
15.5 |
| Cow |
82.6 |
1.6 |
| Opossum
|
19.2 |
23.3 |
| Squirrel
monkey |
17.0 |
22.9 |
| Echidna |
64.2 |
0 |
| Man
|
60.6-76.3 |
6.6-10.6 |
Electroencephograph
dimensions from 11 animals. From:Wallings, P.T. and
K.N. Hicks. "Domensions of consciousness." BUMC
Proceedings 2003:16:162-166 |
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