The Yuo Yowa are remarkably similar to humans from the waist up. They have a large, muscular tail that they use to grip and grab, but also for balance and swimming. Due to the tail's weight, they don't walk as straight as humans, but can rear up to an almost erect position, just like walking and running with their bodies being completely horizontaly positioned. The position of their body and tail is very important in non-verbal communication. The Yuo Yowa are digitigrade, their feet also retaining retractable claws from their ancestors. The first digit on their feet is opposable, used for grabbing onto branches, or gripping onto larger prey.
Due to both pheomelanin and eumelanin present in their skin cells, they can have reddish and yellowish skin tones. When their hair grows, it starts out as dark until the production of eumelanin halts and the hair continues growing light, or with only pheomelanin present. Basicaly like agouti fur in cats and dogs.
When their ancestors, the house cats, started exploiting a niche of a small, arboreal predator, one of them had a nanite mutate its forelimb claws in such a way that they were slightly more opposable. This individual passed it down to their offspring, because it happenned to be an advantage for climbing and prey capture. As the time passed and the ecosystem stabilized more, they began to grow larger as larger prey established their own populations in the rainforests. At this point, their ancestors weighted circa 60 kilograms. Due to their diet shifting to a larger sized prey, they slowly abandoned the tree canopy, but still climbed on their daily basis. One branch of these moderately sized felines would slowly become more and more social, using their opposable thumbs for grabbing rather than restraining. They specialized in hunting larger prey in small groups, ambushing it from the treetops, gripping tightly onto it with their claws and beating it up with rocks and sticks that would be often thrown as well. This behaviour later developed into tool making and more complicated hunting strategies. This lineage then resulted in the Yuo Yowa. What's also interesting is that they're the only sophont in Total Convergence..? that developed menstruation convergently with humans and few other mammals.
Pregnancy lasts for six months and the babies are born blind and with dark hair. They begin to open their eyes after a few weeks. The babies also have very short tails that begin to grow when they're around ten months old and when the tail is proportionaly longer than the child's body, it is considered a sign that the child is ready to start learning how to walk.
The Yuo Yowa are carnivorious, but like to supplement their meals with spices and mushrooms especially. Their diet has to consist of at least 75% meat. Due to that, they never invented farming and thus never experienced a population explosion as drastic as ours, although some population explosions have occured, they were never as large in scale as they were in human history. Those minor explosions were mostly caused by the invention of large scale fishing and mussel farming. This also made them very vulnerable in wars and other political conflicts, because it is simply way harder to obtain meat than to obtain a potato when your country's economy is collapsing.