Novel equipment for monitoring ultrasonic vocalizations

H. van der Wiel and C. van der Leden

MTM, TNO- Defense and Safety, Rijswijk, The Netherlands

Ultrasonic vocalizations (USV) are sounds within the frequency of 20-100 kHz. This frequency range is above the human range of hearing. However, it is well known that bats, dolphins, rodents and insects produce and hear USV as part of their behavior. Rodents use ultrasonic sounds for communication. There is evidence that USV is used as a sensitive indicator of subtle emotional and motivational changes in a number of animals. Therefore, USV produced by animals in various conditions could be explored as a non-invasive method for registering the welfare status of an animal.

Objectives of USV measurement

The use of USV to measure the welfare status of an animal would be advantageous in a number of situations:

  1. at a very early stage of an experiment it is possible to recognize discomfort whereupon pain relief can be administered;
  2. the effectiveness of the pain relief can be measured (monitored).
  3. as a parameter in behavioral studies.
  4. as a monitoring system during transport and acclimatization

USV Measurement

Modern equipment transforms the USV sounds in a for humans audible signal ready for analysis. The very time-consuming and labor-intensive method with a bat detector combined with a tape-recorder is no longer an option for a versatile measurement. TNO-PML developed equipment that monitors USV sounds making use of a microphone, a Personal Computer and LabVIEWTM. In the last few years the importance of ultrasounds on animals has been recognized widely and even an article of law has been made to alert researchers to ultrasounds with respect to animal housing.

What can be achieved

By monitoring the USV sound one can learn much about the well-being of animals. The animal research is re.ned and extended by an objective analysis of USV sounds. USV could lead to:

  • Less discomfort, improvement/monitoring of animal welfare, and better living conditions for laboratory animals.
  • A decrease in the need of laboratory animals because at an earlier stage of an experiment effective countermeasures could be taken.

Paper presented at Measuring Behavior 2005 , 5th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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