Does global warming cause animals to shrink?
A study of copepods found that the growth rates of the tiny marine crustaceans is highly sensitive to temperature, with implications for the entire food chain.
Melting ice, outbreaks of disease, more intense storms and more forest fires are just some of the effects scientists say will accompany human-caused climate change. Scientists are now exploring another, perhaps more surprising, potential effect: Shrinking animals.
A new study has examined how warmer temperatures can result in smaller individuals within a species.
This relationship between size and temperature change only holds for cold-blooded animals, which rely on external sources, such as sunlight, to warm themselves. Scientists don't understand why this relationship exists. But it's important because size influences an individual's reproductive success, as smaller animals tend to have fewer offspring, and its role in a food chain, among other things. [Cold-Blooded Creatures: Album of Lizards & Frogs]
To warm-blooded creatures like humans, this might not sound like a big deal. But we make up only a tiny percentage of Earth's animals, and we rely upon cold-blooded creatures for food, to pollinate crops and for many other crucial, but perhaps not obvious, reasons. So, climate-influenced changes could have cascading effects.
Scientists have already established the "temperature size rule," which says that individual animals reared at colder temperatures will become larger adults. Likewise, animals reared in warmer temperatures produce smaller adults. However, it's unclear just how this happens, according to Jack Forster, a doctoral student at Queen Mary, University of London, and the lead researcher.