That's really clever, especially since it makes perfect sense from a biological perspective for pegasi to reflexively extend their wings when startled or angry. First of all, having the wings pre-extended makes it easier for a pegasus to take off at a moment's notice, which could save its life. Second, spread wings make a pegasus look bigger. This is part of a behavior called a threat display, which is seen in pretty much all animals, including humans. In fact, birds really do this; here's an excellent example. tornfeathers.deviantart.com/ar… Extended wings are quite literally a "fight-or-flight" response.