What kind of society would panthers form if they were smarter than us?

The title pretty much sums it up. I'm creating a fictional world in which there are creatures who started off much like panthers. They're territorial, stealthy, fast hunters. Males controlled a territory of around 30 miles and there were several smaller female territories within each male territory. However, unlike panthers, they are bipedal and have opposable thumbs. They can still use their long tails and powerful legs to run quite rapidly to catch up with prey though. What kind of culture would result if such creatures had an average IQ of, say, around 140?