On this program we teach common words and expressions in American English . Today we talk about an animal found in many parts of the United States -- deer . Washington , D.C . is home to many deer . They are sweet-looking , especially the baby fawns with their white spots . In the city , they are fun to watch , but they do cause trouble . They make a lot of gardeners angry because deer eat almost everything ! In many parts of America , you will see road warning signs about deer . Adults are not little animals . An average male weighs about 135 kilograms ! Deer sometimes leap into the path of fast-moving traffic . This can have serious , sometimes deadly , results . And , that is what brings us to today's expression – like a deer caught in headlights . Deer will often stop suddenly in the middle of a road and stare into the lights of a vehicle coming toward them . They appear frozen in place , or “caught ” in the headlights . When people are in a state of extreme surprise , fear or confusion , we say they are like deer caught in headlights . They do not know what to do , so they do not do anything . Sometimes we shorten the phrase and simply say , “like a deer in headlights .” This is a little different from being called “doe-eyed .” A doe is a grown female deer . People who are doe-eyed are innocent , clueless . They are unaware of what's going on around them . Now , please keep this in mind . We usually use “like a deer caught in headlights ” in situations that are not life-threatening . For example , people who have stage fright often look like a deer in headlights . Let's say I am acting in a play . I know all my lines and feel ready . But on opening night , as I look out into the audience and see all those faces … I freeze . I forget all my lines and stare into space , unable to speak . Someone watching might say , “What is wrong with Anna ? Is she supposed to just stand there doing … nothing ? She's like a deer caught in headlights .” So the next time you are really surprised or scared , you may find yourself looking frozen and wide-eyed -- like a deer in headlights .