Related Experiment Video
Updated: May 4, 2026
10:28
Body Composition and Metabolic Caging Analysis in High Fat Fed Mice
Published on: May 24, 2018
16.3K
Neither rats nor mice have a broad thermoneutral zone: implications for physiological studies
Julie M Jacobsen1, Kent Pedersen1, Magdaléna Vydrová2,3
1Diabetes, Obesity and MASH, Research and Early Development, Novo Nordisk A/S, Denmark.
Communications Biology
|January 16, 2026
Summary
Small mammals like mice and rats experience heat stress at higher ambient temperatures, not a broad thermoneutral zone. Optimal housing temperatures for research are 28-29°C to balance energy expenditure and thermal stress.
Area of Science:
- Physiology
- Animal Science
- Thermoregulation Research
Background:
- Small mammals expend significant energy to maintain core body temperature (Tb).
- Understanding thermoneutral zones (TNZ) is crucial for animal welfare and research accuracy.
Purpose of the Study:
- To investigate how ambient temperature (Ta) influences energy homeostasis and Tb in mice and rats.
- To determine the thermoneutral points (TNP) and thermal tolerance limits for mice and rats.
Main Methods:
- Indirect calorimetry and continuous Tb measurement were used.
- Male mice and rats were studied across a range of ambient temperatures (22°C to 35°C).
Main Results:
- Increased ambient temperature led to higher Tb, decreased food intake, and reduced body weight, indicating heat stress.
- Rats showed signs of thermal distress at 30°C; neither species exhibited a broad TNZ, but rather a TNP.
- Mice displayed increased energy expenditure above TNP due to higher Tb and activity, yet showed reduced basal metabolic rate indicating adaptation.
Conclusions:
- Rats are more susceptible to overheating than mice and less cold-sensitive.
- Both rats and mice possess a TNP, not a broad TNZ, challenging previous assumptions.
- An ambient temperature of 28-29°C is recommended for housing mice and rats to minimize thermoregulatory stress in research settings.
