Creature of the Week: Thanator

Known as the Thanator to the humans. Palulukan (meaning "dry mouth bringer of fear") to the Na'vi, the natives of Pandora. This creature is one that all creatures and people of Pandora know to stay away from. It is a hexapedal animal that lives in the world's forests, preying on anything it can find. Thanator is believed to be the apex predator, considering that all creatures, big or small, carnivore or herbivore, even the Na'vi fear it. The Na'vi are known to be courageous and fantastic hunters, so when they actively avoid a beast such as this, any newcomers know that it's a serious threat. Looking at the physical appearance alone, we can determine that it is indeed a danger. It is pretty much a 20 foot alien panther. These beautiful beasts are lean and agile as well as fast, giving them the upper hand over most other creatures. The Thanators have powerful jaws that they use to catch and tear apart their prey. Even defending yourself against them won't be a very promising decision, since they have armored backs, sharp claws, long teeth, and a powerful tail that they use to defend against other Thanators. Although, if you do your best to avoid their territory and go out during the day, you should be safe since they are night hunters and stay within their established borders. SHOULD be safe. If they come out during the day, there's a good chance they are desperate for food, so be very careful and pray you aren't within their sense range of 8 miles. Some Na'vi clans have made this beast their totems, and have tried many times to try and tame one. All attempts have failed. However in the final battle with the Na'vi vs. Humans, one of the Thanators offered itself to assist Neytiri at the expense of its own life.

Source: Avatar Wiki