Hello I'm Dr. Christine Portfors. I'm an associate professor in the school of biological sciences at Washington State University in Vancouver. Today we are here to talk about what sounds do bats make. Bats make a lot of different sounds. The most well known sounds that they make are called their echo location sounds. And these are the sounds that we actually don't hear most of them. Because the sounds are much higher in frequency then what the human ear can actually hear. So the bats use these sounds when they are flying around, they emit a very high frequency sound out of their mouth or some species emit it out of their nose. And that sound travels out and it travels back and bounces off all of the objects in the environment creating an echo and the bat uses that echo to orient and often to find food, to track moths etcetera. Now how do we know that the bats make those sounds if we can't hear them. Well we use this. This is called a bat detector. And the bat detector is designed to pick up those frequencies that are really, really high and bring them down into our hearing range. So that if you hook this bat detector up to head phones or a speaker you can actually hear those bats flying around. And so on a summer night when you look up, you don't hear any of those bats making any sounds, pull out a bat detector and you can hear how active they actually are in making those sounds. Now some of the sounds that bats make we actually can hear. And for the most part those sounds are the sounds that they use to communicate with each other. And so they are called communication sounds. And if two bats are fighting then they'll make a sound that's like a squawk and mothers will often identify their pup by a signature sound that that pup makes and so the mother is able to identify her pup. So they use these communication sounds for a number of different behaviors. Some bat species will also produce what are referred to songs and these are the males and the males make these sounds to attract the female. And the female then chooses who she wants to mate with based on what the male sings, what sounds he's making. And often those sounds humans can actually hear. So they have echo location sounds that we can not hear, and then they have a whole broad range of social communication sounds. And their range of social communication sounds is an area of research that we don't know that much about. But there's more and more interest in trying to understand how these animals use sounds to communicate with one another.