Durham Bat Group entry page

<body background="images/weave.gif" topmargin="0" leftmargin="2" bgcolor="#ffffee"> <h1><font color="#000080">Durham Bat Group home page</font></h1> <h3><font color="#000080">Dates and venues of bat walks and meetings, Bat calls, reports on bat activity, and NEW! maps of recorded sightings throughout the Durham bat group area.</font></h3> <table border="0" cellspacing="1" width="100%" id="AutoNumber1"> <tr> <td width="220"> <img border="0" src="images/durbatlogo.gif" width="315" height="265"></td> <td width="100%" valign="top"><font color="#400080" ><strong>Introduction:  What Are Bats?</strong></font><br> Bats (Chiroptera) are mammals that have evolved to fly.   My interest is mostly in British bats (MicroChiroptera). These feed on flying insects and avoid predators by hunting just after dusk and sometimes before dawn. (They are 'crepuscular'.) Bats are warm blooded, so prefer warm conditions, and they hibernate when it is cold.  Although their sight is quite good, they use sonar to help them navigate around obstacles and locate their prey in the dark</td> </tr> <tr> <td width="220">  </td> <td width="100%" valign="top"> </td> </tr> <tr> <td width="220"> <img border="0" src="images/sonar.gif" width="220" height="158"></td> <td width="100%" valign="top">The bat makes a loud noise, at a pitch above our hearing range. (Long eared bats have super sensitive hearing and so can use quieter sounds.) The reflected sound is interpreted by the bat to form a kind of picture of its surroundings. We can transform the sound from the bat to a lower pitch with a bat detector, so that we can hear it. The sound playing now is from a pipistrelle, recorded using a heterodyne detector.</td> </tr> <tr> <td width="220">  </td> <td width="100%" valign="top"> </td> </tr> <tr> <td width="220">  </td> <td width="100%" valign="top"> </td> </tr> <tr> <td width="220">  </td> <td width="100%" valign="top"> </td> </tr> </table> <a href="hetero.htm" target="main">Heterodyne</a><br> <a href="fdiv.htm" target="main">Frequency division</a><br> <a href="timex.htm" target="main">Ti</a></font></p> <h1><font color="#000080">web design by webmasters@skillbank.co.uk</font></h1> <p>BTW: If you had a better browser you'd get sound, animation and other benefits, and really see this site at its best! </p> </body>