IMO melanistic jaguars are regal, magnificent animals. Most people don't realize how intelligent jaguars are. It's said that if you enter the Amazon, the jaguars know you're there and they're watching you even though you don't see them. They choose to leave humans alone, except for rare instances when humans threaten their cubs.
Unfortunately, since China has exterminated the wild tiger population to feed it's endless appetite for big cat body parts for use in traditional Chinese medicine (aka quackery), Chinese poachers have now turned to poaching jaguars. Poaching is up more than 200% in the Pantanal. If you can, please donate to the groups trying to protect jaguars from poachers.