It was the worst of times for five juvenile grey squirrel siblings in the US state of Wisconsin when their tails became potentially fatally entangled with grass, plastic and each other.

The rodents became trapped in the nest their mother had built, after their tails worked themselves into a giant knot.

A “caring finder” found the infants, known as kits, and took them to the Wildlife Rehabilitation Centre at the Wisconsin Humane Society.

“You can imagine how wiggly and unruly (and nippy!) this frightened, distressed ball of squirrelly energy was, so our first step was to anaesthetise all five of them at the same time,” the centre wrote on its Facebook page.

With the animals out cold, the centre began work to unravel the “Gordian Knot” of tightly tangled tails and nest material.

All five squirrels recovered after their anaesthetic. Photograph: Wildlife Rehabilitation Center at Wisconsin Humane Society

“It was impossible to tell whose tail was whose, and we were increasingly concerned because all of them had suffered from varying degrees of tissue damage to their tails caused by circulatory impairment,” the centre said.

After about 20 minutes of careful cutting the knot began to undo and the squirrels were left to recover from their anaesthetic.

The squirrels appear to be unaffected by their experience. Photograph: Wildlife Rehabilitation Center at Wisconsin Humane Society

“Now, one day later, they are all bright-eyed, and three of the five are ‘bushy-tailed’, but we’ll need to monitor all of them for a couple of days to watch for tail necrosis caused by impaired blood flow,” the centre said.

Grey squirrels are members of the rodent family can grow up to 50cm (21 inches) in length. They live throughout Wisconsin, preferring mature hardwood forests where they feed on acorns, hickory nuts and walnuts.