The ring-tailed primate, native to Madagascar, was found in freezing sub-zero conditions.
A severely ill lemur was discovered on Tooting Common on Tuesday.
The ring-tailed primate, which is native to Madagascar in Africa, was found in sub-zero conditions and later diagnosed with hypothermia at the Blue Cross animal hospital in Victoria.
The lemur, named King Julien after the animated film “Madagascar”, was put on a drip and taken to the hospital’s isolation unit for further monitoring.
Blue Cross chief vet at the Victoria animal hospital said: “We were very concerned about King Julien’s health as he was very cold, scared and didn’t want to eat.
“But our nurses managed to coax him into taking some drops of honey from a syringe, then he gradually started eating bits of banana and grapes.”
The animal charity said that it was not known how the animal, which is required by law to have an exotic animal license, had come to be on Tooting Common.
Mr Bossley added: “We mainly treat cats and dogs at the Blue Cross but we do get the odd snake or tortoise, and we have been known to treat chickens, goats and even possums.
“But this has got to be the most unusual animal we’ve ever taken in. How a ring-tailed lemur turned up in Tooting Common, I’ll never know.”
The lemur is said to be recovering well and will soon be strong enough to leave the hospital.
King Julien will be transferred to the Specialist Wildlife Services who will try to rehome him.