THEY are among the planet’s most-loved creatures, celebrated for making sure presents for good boys and girls arrive safely and on time.

But Scottish scientists have now discovered it might take a few more reindeer to pull Santa’s sleigh this Christmas, with new evidence showing that the animals are shrinking.

Lead researcher Professor Steve Albon, from the James Hutton Institute, said Arctic reindeer are becoming smaller and lighter due to the impact of climate change on their food supplies.

Over a period of 16 years between 1994 and 2010, the weight of adult reindeer studied in Svalbard, a group of islands near the North Pole, fell by 12 per cent from 55kg to just over 48kg.

Warm winters are producing more rain which then freezes on snow, covering the pasture beneath with a layer of ice that the deer cannot break through.

Prof Albon said: “The implications are that there may well be more smaller reindeer in the coming decades but possibly at risk of catastrophic die-offs because of increased ice.”