Scientists made their 25th visit to the Scottish Island of Hirta in the Outer Hebrides to complete a study and made a stunning discovery; the sheep on the island were shrinking, literally.

Each year of the study the sheep shrank by 81g, about 5% of their body mass, and scientist think that this is because of climate change rather than natural adaptation.

Natural changes would have led to larger body sizes, not the smaller body mass that was exhibited.

The sheep on the island are not tended, which is why the change is evident as farmers choose sheep based on their size to get the highest profits, which is why the fall in the sheeps' mass may have gone unnoticed previously.

Humans have also altered in size, as the average height in the UK has increased over 5cm over the last century due to different nutrition patterns.

Additionally, medicine advances have increased the average Briton's lifespan approximately five hours a day.

Yet, Professor Coulson, co-author of the paper and specialist at Imperial College in London in population biology, said that humans that were not affected by cultural and technological change like the sheep on the island could also show signs of climate change.

Coulson went on to state that a rising number of climate change related alterations have been observed in animals such as marine iguanas, fish, North American squirrels, and sticklebacks.

The Hirta study started in 1986 and involved 30 separate surveys of the sheep who were measured as lambs, yearlings, and then at various times throughout adulthood.