How do you measure a rat's temperature? - briefly
Insert a lubricated, flexible thermocouple or digital probe 2 cm into the rectum to obtain core temperature, recording the value after ≈30 seconds of stabilization. For rapid screening, an infrared camera aimed at the dorsal surface can estimate temperature, though accuracy is lower than rectal measurement.
How do you measure a rat's temperature? - in detail
Measuring a rodent’s core temperature requires selection of an appropriate method, preparation of the animal, and correct use of equipment.
Rectal thermometry remains the gold‑standard for acute measurements. A lubricated, flexible probe (typically 1.5–2 mm in diameter) is inserted 2–3 cm into the anal canal. The probe is connected to a digital thermometer with a fast response time (≤1 s). Readings stabilize within a few seconds.
Infrared thermography provides non‑contact surface temperature. A calibrated infrared camera is aimed at the dorsal thorax or the ear pinna. Ambient temperature and emissivity settings must be adjusted to avoid systematic error. Surface readings correlate with core values only after validation against rectal data.
Tympanic thermometers, designed for small mammals, measure temperature in the ear canal. A disposable probe tip is inserted gently; the device displays an averaged value after a brief acquisition period. Accuracy depends on proper placement and ear canal size.
Implanted telemetry offers continuous monitoring in freely moving animals. A miniature temperature sensor is surgically placed intra‑abdominally or subcutaneously and linked to a radio‑frequency transmitter. Post‑operative recovery and device calibration are essential for reliable long‑term data.
Standard operating procedure for any method includes:
- Acclimatization of the rat to handling to reduce stress‑induced hyperthermia.
- Confirmation of probe sterilization or sensor integrity before each use.
- Recording ambient temperature and humidity to allow correction of surface measurements.
- Verification of device calibration against a certified reference thermometer at regular intervals.
Data handling:
- Log each measurement with timestamp, animal identifier, and method used.
- Apply appropriate statistical analysis to compare groups, accounting for repeated measures when telemetry is employed.
- Report temperature in degrees Celsius with precision to one decimal place.
Safety considerations:
- Use appropriate anesthesia or sedation for invasive probes to minimize discomfort.
- Monitor respiration and heart rate during and after the procedure.
- Dispose of single‑use probe covers according to biohazard protocols.
Choosing the technique aligns with experimental goals: acute, high‑precision core values favor rectal thermometry; longitudinal studies benefit from telemetry; non‑invasive assessments may employ infrared or tympanic devices after validation.