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Research led by Dr Kirsty Macleod from its School of Environmental and Natural Sciences, found that lizards whose mothers experienced stress during pregnancy grew more slowly and behaved differently. 

Surprisingly, the paper, published in the revealed that these stressed offspring were actually more social. They spent more time with other lizards, including their mother and siblings.  

However, the research also found that unlike some other animals (including humans), baby lizards spending time with their mother after birth did not reduce the effects of the prenatal stress. 

To conduct the study, the researchers looked at a type of Australian lizard called Liopholis whitii, which live in family groups, and tested how stress hormones given to mothers during pregnancy affected their offspring. The treatment is designed to mimic the short-term increase in hormones that an animal experiences when it encounters a predator or similar natural stressor. 

Some baby lizards were raised with their mother for a few weeks, while others were raised alone, to see if being with their mother could help reduce the impact of prenatal stress. 

These effects suggest that maternal stress is an important factor in how lizards behave socially and that it even overrides the influence of the social environment in the early period after birth. The findings have potential implications for understanding how social groups form in animals like lizards. 

Dr Kirsty Macleod from Bangor University’s School of Environmental and Natural Sciences said, “Stress during pregnancy can affect how offspring grow and behave, including how they interact with others. In some animals, a supportive social environment after birth — like time spent with a parent — can reduce or ‘buffer’ the negative effects of early stress. However, scientists know less about how this works for simpler behaviours, such as whether a parent simply tolerates being near their young. 

“This study shows that stress experienced by lizard mothers during pregnancy can have long-lasting effects on their young, particularly on how social they are. It also suggests that, at least in these lizards, simply being near a parent after birth isn’t enough to undo the effects of prenatal stress. These findings help us better understand how social behaviour develops and how family groups might form in the wild.”