Some warm-blooded animals are undergoing changes in body shapes, most likely as a result of climate change pressures, according to new reviewing existing research.
A few examples are some Australian parrot species, where their beaks increased by 4-10% since 1871, and have seen a positive correlation with their summer temperature each year.
She said the changes are subtle and unlikely to be immediate but could be ‘operational’.
While global warming is “compelling argument” the diversity of the impact of climate change on the environment makes it difficult “establish causality with confidence” said the study.
Within a given animal species individuals in warmer climates have larger appendages including wings and beaks, a pattern known as Allen’s rule, where the larger surface area allows them to more easily control their temperature, said the study.
At the same time, sizes shrink because smaller bodies absorb less heat.
In the US, a recent study of 70,716 migratory birds representing 52 species showed that over the last four decades they have decreased in size and increased in wingspan.
The full results of the study were presented in the journal Trends in Ecology & Evolution.
