The men entered the Sibuya Game Reserve on the southeast coast armed with a high-powered rifle and an axe in the early hours of Monday and were found dismembered the following day.
“They strayed into a pride of lions – it’s a big pride so they didn’t have too much time,” reserve owner Nick Fox, 60, told AFP.
“We’re not sure how many there were – there’s not much left of them.
“There seems to be clothing for three people. I’ve not heard of it before in our area.”
Police forensics officers were on the scene conducting tests on the remains of the victims, Fox added.
“We went in yesterday – I got our vet to dart [anaesthetise] all the lions,” he said.
“I think we had a stroke of luck here that the lions got to them before they got to the rhinos.
“We lost three rhinos in March 2016.”
Fewer than 25,000 rhinos remain in the wild in Africa due to a surge in poaching.
Rhinos are targeted to feed booming demand for rhino horn in China, Vietnam and other Asian countries, where it is believed to have medicinal qualities.
Fox said that the reserve was still open to guests despite the incident.
“It’s still business as usual, it doesn’t change anything we do,” he said.