帮忙翻译下BBC文章
Since1999,researcherswiththeElephantListeningProjecthaveusedanacousticmonitoringsystemtorecordelephantsoundsintheAfricanrainforest.
They’velearntthatelephantsuseinfrasoniccalls-callstoolowinfrequencytobeheardbythehumanear-forlong-distancecommunication.Infrasoundcantravelfartherthanhigherpitchedsound.Elephantfamiliesseparatedbyseveralkilometersusethemtokeeptrackofeachother.Maleelephantsfindfertilefemalesbyusingtheselowfrequencysounds.
ElephantpopulationsinAfricaaredecreasingduetoencroachinghumancivilization.But,evenaswehumanshavebecomestewardstotheelephants,it’shardtoknowexactlyhowmanyelephantsareleft.ElephantsinthedenseforestsofAfricaaredifficulttocount.Sightingsarerare.TheElephantListeningProjectcanusetheelephant’scallstodeterminethesizeandhealthoftheherds.Atleastonesuchstudywasusedtolocatehotspotsofelephantactivity.
Andit’snotjusttheelephants'soundsthatgetmonitored.Therecordersalsopickuphumansounds-gunshots,chainsawsandvehiclenoise-whichhelptoidentifypotentialthreatstoforestelephantpopulations.
Andfortodaythat’sourshow.Wedohopeyoucometoourwebsitetoletusknowwhatyouthinkatearthsky.org.We’reBlockandByrdforEarthandSky.