Daniel Rotman wishes he had been able to tell sooner that his cat was sick.

Rotman says that in 2010, he started noticing that his cat, Gingi, wasn’t her normal self. He brought her into a veterinarian’s office, and Gingi was later diagnosed with feline leukemia. Not long after that, she passed away.

“Cats are notoriously stoic creatures,” Rotman says. “They hide their illnesses very well.”

Many owners don’t realize their cats have become sick until they stop eating, he says, or begin to act lethargic or urinate outside their litter boxes. Read the full story here.