Vocalization in Rats

[nightshade]

I have been curious for some time as to wether Rats call at inaudible levels
and despite random attempts to find out have not had too much sucess
But I have a family (probably be 2000 soon) of Brown Rats living under a
neighbours shed and armed only with my Pettersson Bat Detector I listened
out for them the only definite sound I could attribute to them was from an adult
foraging that suddenly realised it was not alone (when it came upon me all
of a sudden) two smaller Rats reacted immediately and fled back the way they
had come
I made the simple mistake of tuning to try and get more sounds instead of noting
the frequency of the alarm
Anyway here are some Professional recordings just for interest;
Norway Rat Vocalizations

[eeyore]

our pet rats call on about 45khz - though they seem able to vary the freq depending on the nature of the call - also when they tooth chatter (which they do when happy) which is aubible it also produces ultasound arround 90khz