Scotland's animal welfare charity was contacted after the tiny cubs were discovered on Broom Road East in Newton Mearns on March 7.
The day-old siblings are now receiving around the clock care at the charity's National Wildlife Rescue Centre in Fishcross, Clackmannanshire.
They have been named Misty, Frosty, Hazey and Sunny after the mixed weather on the day they were found.
Animal Rescue Officer Ashley Griffin said, "Sadly, there was no sign of the cubs' mother anywhere.
"They were so young they still had their umbilical cords attached and were extremely cold so it's very lucky they were found.
"I put the cubs into a box with lots of towels and kept my van heater on high to keep them as warm as possible on the way to our wildlife centre.
"It's great they are doing well in our care and that they have each other as this will really help with their development."
Centre manager Colin Seddon said, "The cubs were just a few days old when they were rescued and wouldn't have survived if they hadn't been spotted.
"There are two males and two females and they are all feeding well from the bottle.
"Wildlife assistant Lorin Willison has been providing the cubs with round the clock care, which includes taking them home at night to continue their hand feeding, but we'll adopt a completely hands-off approach as soon they're old enough to feed themselves.
"The cubs will be released at a carefully selected site when they are at the right age and stage to be able to survive on their own in the wild."
Anyone who discovers an injured or distressed animal should call the Scottish SPCA Animal Helpline on 03000 999 999.