Toothless is very intelligent and seems to have a dry sense of humor, similar to Hiccup's, which he may have piked up from Hiccup. He doesn't take kindly to being offended or anyone offending or endangering his human friend but is usually playful, docile, maybe even a little teasing when not threatened. He also shows a great curiosity, imitating Hiccup's actions and mannerisms when they initially encounter one another like when he was observing Hiccup draw him, he then tries to draw with a tree branch. Toothless' intelligence shows many times throughout the film, being able to understand Hiccup's words and commands as well as agree with some of what he says. It is shown that he has become aware of Hiccup's crush on Astrid, even seeming to briefly tease him about it.