London (dpa) - Certain dogs can detect when their diabetic owners are suffering from low glucose levels and are likely to sink into coma, the British Medical Journal reports.

The dogs react strongly, informing their owners in their own different ways of the need to act to counter hypoglycaemia.

Writing in the BMJ, Gareth Williams and Mimi Chen of University Hospital, Liverpool, and Mark Daly of Wansbeck General Hospital, Ashington, describe the dogs' unusual life-saving abilities, citing three cases.

The team believes about a third of dogs living with diabetics show changes in behaviour during hypoglycaemic episodes, when control of blood sugar becomes dangerously low.

Natt, a three-year-old golden retriever, can detect when his owner is about to go into coma through the bedroom door while asleep. He barks and scrabbles on the door to wake her up and only settles when she has stabilised her condition.

He paces up and down, or puts his head in the lap of his owner, a 34-year-old woman, when he becomes aware of hypoglycaemia. Like the other two dogs, he will only settle when he is sure that all is well.

Candy, a nine-year-old mongrel bitch, jumps up, runs out of the room and hides under a chair in the hall when her owner, a 66-year-old woman, suffers hypoglycaemic symptoms, even though she is often unaware of it.

Candy re-emerges only when her owner has eaten and is comfortable again.

Susie, a seven-year-old mongrel bitch, will not leave the house, or turns down her favourite chocolate treats, if she suspects that her owner, Gwendoline Ball, 47, is hypoglycaemic. Sometimes she nudges her awake at night.

The team is not sure how the dogs become aware of the condition of their owners.

"All were clearly able to sense hypoglycaemia accurately under circumstances when the patients themselves were initially unaware of falling glucose levels," the team said.

"Susie and Natt deserve special mention because they were able to detect nocturnal epsiodes in their owners and then undertook further corrective action by waking them to eat - thus going further than any available glucose meter."

The dogs could be noticing changes in smell, caused by sweating, muscle tremor, or behavioural alterations such as failing to respond to the dog in the normal way.

"We are attracted by the notion of the sixth sense, with which dogs are commonly credited, but acknowledge that this will need to be substantiated by further research," the team says.

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