Posted Aug 21, 2011
With bright orange cheeks, speckled feathers and a chirpy song, the zebra finch may seem like it hasn’t a care in the world.But Scottish research shows that, just like humans, they can be affected by stress and suffer the long-term consequences.The study by a team at Glasgow University found that the small birds can reveal a lot about how stress in early life could affect human life expectancy.
According to the research, even if someone was not exposed to stress near the start of life, living with a partner who was could also shorten their lifespan. Lead researcher Pat Monaghan said: “The take home message is that the wrong kind of partner can be very bad for your health.”
For the study, the researchers used zebra finches as a measure of how vertebrate animals respond to stress. Half the birds were fed a dose of stress hormones as chicks for two weeks, while the others were not. All the birds were then kept in the same stress-free environment until they became adults.
The researchers saw that those birds exposed to stress in early life reacted to stress much more than the other more “laid- back” birds who were not fed the stress hormones.While being sensitive to stress can help make animals alert to dangers such as attacks from predators, stress hormones are known to have a negative effect on the body’s other functions and so can be bad for health.
The birds were then paired and allowed to breed, with the rest of their lifespan monitored. The researchers discovered that those birds exposed to stress at the start of life had shorter lives as adults.Even if the bird had not been exposed to stress, being matched to a stressed partner also shortened their lifespan. The worst position by far was for two stressed birds to be paired together.
The researchers said a reason for this may be that “jittery” individuals are not very comforting to be with.Prof Monaghan said: “If the partner was also a bird that did not have stress in early life, after three years only 5 per cent had died. If they were a normal bird but their partner was one of the birds that had had stress in early life, after three years 20 per cent of them had died.
The effect of having a partner who was stressed in early life is to increase your risk of death by four times.”The researcher said that where both birds had been exposed to stress, the risk of dying was eight times higher.The researchers believe the findings would also apply to humans exposed to stress in early life, such as children experiencing poor nutrition or living in a constant fear of danger.
Dr Eva Cyhlarova, head of research at the Mental Health Foundation said: “Given the relationship between poor mental health and lower life expectancy, we would therefore not be surprised if research among humans yielded similar results”.
Bird in bush
The zebra finch is commonly found in Australia, living in grasslands and forests, usually close to water.It grows to a size of about 10cm (3.9in) long and feeds on grass seeds and spray millet.The finches are loud and boisterous singers, making sounds such as “beep”, “meep”, “oi!” and “a-ha!”.Their song is described as a few small beeps leading up to a rhythmic melody of varying complexity in males.The birds are widely kept by genetic researchers, those breeding as a hobby and pet owners.