Though we have chosen to focus on the Shrinking Soay sheep of St. Kilda, they are merely an example to use as a possible indicator for larger issues at hand.

If it is climate change that causes the shrinking of Soay Sheep, are all the animals going to decrease in size ?

The shrinking body size of the Soay sheep may be used as an indicator for other species, who may also notice a quick reduction in body size. The fact that they live on an isolated island uninhabited by humans means that studying these wild sheep is easier than otherwise.

The changes seen amongst the Soay sheep may be witnessed in other species in years to come. Other species as well, such as ectotherms – animals that control body temperature through external means, such as frogs, have noticeably shrunk over the past years. American biologist Jennifer Sheridan explains that as temperature rises, the ecotherms’ metabolism rises. In order to keep up with the metabolism change, they must either consume more, or more likely, they do not grow to be as large. For other endotherms, animals that produce heat through internal means, like all the mammals, Sheridan explains that they are less directly effected by a shift in climate, and more by a change in available resources.

All in all, if species actually start to shrink like a few scientists predict, the question of food sources may become problematic in centuries to come – but there is absolutely no scientific consensus about this issue.

Could humans start shrinking too?

Today, it is the opposite trend that can be noticed among humans: they are getting taller and taller – the 2012 average human is 10cm taller than in 1900. It is for the moment very unlikely that the research done showing the shrinking of species applies to humans, even if it is not impossible in centuries to come.

However, the shrinking other species, including other types of mammals and as well plants, can definitely have an effect amongst mankind, through food shortage issues as we’ve seen, but not only. One of the scientists we interviewed – israeli zoologist Yoram Yom-Tov – already stated that human activity does affect species, so it’s not out of the question that human activity will affect people too. Already, fruits are shrinking and droughts are more common due to the effect humans have had already on climate change.

Soay sheep: an isolated case study

The Soay sheep are an example of how species are adjusting to the changing environments of planet earth, however not all animals are shrinking and they cannot be used as a model for what is going to happen in general. Many species have as of yet not seen a shift in body size over recent years, while others, such as the Eurasian otter (Lutra lutra) in Sweden is growing due to climate change, as seen by studies by Yom-Tov. Change in species size may be due to the increase of C02 in the atmosphere, which forces average temperatures to rise, or it may be due to human activity affecting their habitats.

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