How to measure a rat's temperature?

How to measure a rat's temperature? - briefly

Use a calibrated rectal probe inserted 1–2 cm into the rectum and read the stabilized value, or employ a non‑contact infrared sensor aimed at the ventral surface for a rapid estimate.

How to measure a rat's temperature? - in detail

Accurate assessment of a rodent’s core temperature requires preparation, appropriate instrumentation, and consistent technique.

First, select a device suited for small mammals. Common options include rectal thermometers with flexible probes (1–2 mm diameter), infrared ear or temporal artery scanners, and implanted telemetric transmitters. Each method has specific advantages: rectal probes provide direct core readings; infrared scanners allow rapid, non‑invasive measurements; telemetry offers continuous data without handling stress.

Second, condition the animal. Acclimate the rat to the testing environment for at least 10 minutes to reduce stress‑induced hyperthermia. Handle gently and restrain using a soft cloth or a dedicated restrainer that permits access to the measurement site while minimizing movement.

Third, calibrate the instrument. Verify the thermometer against a certified reference point (e.g., ice bath at 0 °C and boiling water at 100 °C) before each session. Record the calibration values and adjust the device if necessary.

Fourth, perform the measurement:

• Rectal method:

  1. Lubricate the probe with sterile, water‑based gel.
  2. Insert the tip 2–3 mm beyond the anal verge, avoiding excessive depth that could cause injury.
  3. Wait until the display stabilizes (typically 5–10 seconds).
  4. Withdraw the probe gently and clean it with disinfectant.

• Infrared method:

  1. Position the scanner 1–2 cm from the ear canal or temporal region.
  2. Ensure the animal’s fur is flattened to expose the skin surface.
  3. Trigger the measurement and record the reading within the device’s response time (usually <1 second).

• Telemetry method:

  1. Implant the transmitter surgically under anesthesia following aseptic technique.
  2. Allow a recovery period of 7–10 days before data collection.
  3. Capture temperature data wirelessly at predetermined intervals.

Fifth, document the results. Include animal identifier, age, sex, ambient temperature, time of day, measurement method, and any deviations from the protocol. Store data in a secure, backed‑up database for later analysis.

Finally, adhere to ethical standards. Obtain institutional approval, use the least invasive method compatible with experimental goals, and apply analgesia or anesthesia when required. Continuous monitoring of the animal’s wellbeing throughout the procedure is mandatory.