Let sleeping bears lie . . .
QUESTION Do bears truly hibernate? HIBERNATION is an extended period of deep sleep that allows animals to survive winter extremes.
Animals that hibernate include some bats, various rodents, mouse lemurs, certain types of snakes, marsupials and the ground squirrel or groundhog, which inspired the movie Groundhog Day.
The scientific description of hibernation is ‘ a long- term state in which body temperature is significantly decreased, metabolism slows drastically and the animal enters a torpor that takes some time to recover from’.
By this definition, bears don’t hibernate, because their body temperature drops only slightly and they can awake relatively easily.
The body of a true hibernator such as a ground squirrel is reduced to near freezing during hibernation. In contrast, bears reduce their body temperatures only by ten degrees Fahrenheit or so. Consequently, some biologists refer to a bear’s winter lethargy or winter sleep.
Other scientists believe that bears exhibit a special case of hibernation. Black bears and brown bears can go for months without eating, drinking or passing waste, unlike ground squirrels, which wake weekly to eat and pass waste.
Bears also have a remarkable ability to retain muscle integrity during their winter lethargy. To do this, they use urea, a component of urine that is produced during tissue breakdown.
The nitrogen in the urea enables them to build new proteins, which they use to maintain organ and muscle tissue.
Ian Giles, Ullapool, Highlands.
QUESTION How did the Isle Of Dogs get its name? THE Isle of Dogs refers to the land within a meander of the River Thames in East London.
In high Victorian style, B. H. Cowper wrote that the Isle of Dogs is ‘embosomed by our noble river, which describes a magnificent curve in the form of a horseshoe from Limehouse to Blackwall’.
The Isle of Dogs is one of the most debated place names in the British Isles. There are many theories as to its origin, none of them conclusive. The name Isle of Dogs was first used in the 1520 Book Of Accounts Of The King’s Ships. Before this, the area was called Stepney Marsh.
It is popularly thought to have got its name because it was home to the royal hunting dogs.
The first written mention of this theory can be found in the 1720 book, Strype’s Stow’s Survey, by ecclesiastical historian and biographer John Strype (1643-1737).
‘The fertile Soil of the Marsh here is much admired, usually known by the Name of The Isle of Dogs: So called, because, when our former Princes made Greenwich their Country Seat, and used it for Hunting, (they say) the Kennels for their Dogs were kept on this Marsh; which usually making a great Noise, the Seamen and others thereupon called the Place The Isle of Dogs: Though it is not an Isle, indeed, scarce a Peninsula, the Neck being about a Mile in length.’
In 1805, English topographer and novelist James Norris Brewer dismissed this idea in The Beauties Of England And Wales: ‘A futile tradition says that the place derives its name from the King’s hounds having been kept there when the Royal Family resided formerly at Greenwich Palace, which lies opposite.’
It would have been highly unusual to describe the royal hunting pack as dogs — they would have been called hounds.
Nevertheless, the 1898 Brewer’s Dictionary Of Phrase And Fable stated that the Isle of Dogs was: ‘So called from being the receptacle of the greyhounds of Edward III.’
Strype also outlined another origin, the spurious story of a murdered man whose body was discovered by his faithful hound crossing the marshes to find him. Other theories include the idea that the Isle of Dogs was originally the Isle of Doggers, from the 14th- century fishing vessels known as doggers; that it was once called the Isle of Ducks; or that it alluded to the Canary Islands, because Insulae
Canariae is Latin for ‘ island of dogs’. Perhaps it was simply a term of abuse.
A neat theory relates back to the first reference in the 1520 Book Of Accounts Of The King’s Ships, which describes the movements of ‘the King’s barkes’ down the river. A ‘barke’ or ‘bark’ was a small ship with sails, so perhaps the name was a pun on this.
It’s a nice thought, but in truth we don’t know how the Isle of Dogs got its name.
Richard Harrison, London SE12.
QUESTION Why do we usually forget dreams as soon as we wake up, yet conscious memories stay with us for years? Are they processed in different parts of the brain? IT IS during the REM, or Rapid Eye Movement, phase of sleep when we tend to do our dreaming.
At this point, our bodies are paralysed to prevent us from acting out our dreams, while our eyes move in reaction to what we’re dreaming about.
It is widely thought that dreaming is a process whereby we filter out clutter — information that isn’t important. We forget our dreams because our unconsciousness registers them as irrelevant.
On a chemical level, it has been shown that norepinephrine, a neurotransmitter used in memory, is practically nonexistent in the cerebral cortex during dreaming, and that electrical activity in areas key to long-term memory, such as the prefrontal cortex, is very low.
Francis Crick, the co- discoverer of DNA, maintained an evolutionary role in dreams. His idea was that the function of dreams is to declutter the brain by weeding out unneeded memory connections that accumulate over time in the brain.
Remembering all of our dreams would leave the brain cluttered with useless information.
Dr Ken Warren, Glasgow.
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