The booming popularity of acorn-based products is putting the squirrel population in South Korea at risk as human foragers steal the rodent's staple diet.
In the Republic of Korea, where human foraging is said to be at an all-time high, there are fewer acorns on the ground and as a result fewer squirrels.
Coming in to save the day for the hungry squirrels are 'Acorn Rangers'.
The team of dedicated animal saviours are policing university campuses and public parks across the Asian nation and scaring off acorn-foraging humans.
The volunteers have no legal authority to punish those they find, but hope to at least deter human foragers from returning.
They spend an hour each week, warning humans away and hiding acorns under tree leaves in an effort to help out the hungry rodents.
In South Korea food which is made from acorns, including noodles, jelly and powder, has grown in popularity after it was declared a healthy superfood that had the potential to fight obesity and diabetes.
As a result foraging for these ingredients has becoming increasingly common at green campuses, popular hiking trails and anywhere where the oak tree is a common feature of the landscape.
It is not however, legal.
But this does not appear to be a deterrent for the acorn-hungry humans.
The Korea Forest Service told The Wall Street Journal that in the last five years the number of those illegally gathering 'forest products' has gone up five-fold.
Those who are caught face up to five years in prison - or a fine of $40,000.
'With acorns being advertised as a superfood, people won't stop,' said Kim Soo-ji, a worker at the South Korean government's forest environment conservation division.
It is a fad that is also spreading into Western Europe and the United States with a number of acorn-derived food, drink and skin products hitting their shelves.
But it is a fad that is putting squirrels and other animals who rely on the nut, and the oak trees they come from, for sustenance.
A researcher at the National Institute of Forest Science Park Chan-ryul said squirrels needed more than 100 acorns in order to survive the cold wintry season.
But if humans continue to forage for their main source of food there will be no more acorns fifty years from now in South Korea.
'We should sympathise with the squirrels' hardship,' he told the WSJ.