Other prospective kitten owners need not fear though, because there are a number of felines still looking for a new place to call their own.
"There are plenty here, and there are plenty more on the way," Brown said.
"We have another 10-plus being desexed on Wednesday."
Brown said kitten season could continue right through until May.
"Herculine might be gone, but come and get a different one instead.
"They're all very, very cute."
All kittens who go through the SPCA are desexed before being adopted.
Tortoiseshells are defined by their two non-white colour combinations and are almost exclusively female. Males carry an extra X (XXY) chromosome and are often sterile but Herculine was still desexed in line with SPCA policy.