The Invisible Welfare Check: Rodent Temperature as a Welfare Signal

When a child feels unwell, the first thing a parent checks is temperature. In laboratory animal research, temperature gets far less attention than body weight or clinical scoring.

That gap is where the topic of Jose Gadea’s AALAS Tech Talk, The Invisible Welfare Check: Why You Should Be Concerned About Your Rodents’ Temperature, presented on October 25, 2026 at the 77th AALAS National Meeting in Houston. The point was straightforward: continuous temperature monitoring creates an ongoing, objective welfare check that runs even when no one is in the room and that’s what makes it useful.

Download the presentation (PDF, 22 slides, 2.1 MB).

Temperature Can Change Before the Signs Do

Body temperature reflects infection, inflammation, stress, anesthesia, metabolism, and disease progression. Depending on the model and the severity, animals may develop fever or hypothermia, so the direction alone is not the whole story.

What matters as much as the value is the pattern. How quickly is temperature changing? How long does the change last? Does the animal recover? Those questions can be more useful than any one measurement, and in several disease models they provide an early indication that something is wrong.

Botulism: Temperature as a Marker of Treatment Response

A 2025 rat study in Molecular Medicine investigated 3,4-diaminopyridine, a potassium channel blocker, as a treatment for botulinum neurotoxin intoxication. Alongside survival and clinical signs, the researchers tracked core body temperature using implanted UID temperature-sensing microchips, read with a handheld UID reader.

As animals became intoxicated, temperature declined — in some cases before overt clinical symptoms appeared. Animals that responded to treatment recovered their temperature quickly. The authors concluded that core body temperature was a reliable biomarker of both intoxication progression and therapeutic efficacy.

Temperature was not only a welfare measurement here. It separated animals responding to treatment from animals continuing to deteriorate. Read O’Brien et al. (2025).

The Snapshot Problem

Most welfare observations are scheduled. Physiology is not.

A typical schedule means a morning check, perhaps an afternoon check, and a recorded observation. The question Jose posed is what happens in between? Events occur overnight, over weekends, and in the hours between rounds. By the time visible clinical signs appear, the underlying physiological change may already be well advanced.

A 2023 study combining a ketogenic diet with 2-deoxy-D-glucose illustrates the point. Continuous monitoring captured sharp, deep temperature declines that resolved and recurred over the course of days. Measured once or twice daily, those episodes could have been missed entirely depending on when the reading was taken. That study used UID UCT-2112 microchips, a URH-1HP handheld reader, and Mouse Matrix. Read Zielinski et al. (2023).

Intermittent data can miss the onset, the severity, and the recovery profile. It attempts to characterize a continuous biological process using occasional observations.

Baselines and Circadian Context

Not every mouse has the same baseline temperature, and temperature naturally rises and falls across the light and dark cycle. A single number means little without knowing what is normal for that animal at that hour.

Continuous monitoring establishes that baseline, which makes more useful questions possible:

• Departure. How far has temperature moved from this animal’s own normal?
• Duration. Is the change brief, or is it sustained?
• Recovery. Does temperature return toward baseline after a treatment or procedure?

A sustained decline from an individual’s established pattern is often more informative than any single reading compared against a population average.

It Changes the Question You Can Ask

Intermittent monitoring answers one question: what was the temperature at the moment of the check? Continuous monitoring answers a better one: how did temperature change across the whole day, the night, the treatment, or the disease course?

A 2026 study in Proceedings of the Royal Society B shows what that looks like. Researchers recorded near-continuous body temperature in deer mice for ten days before and ten days after an immune challenge. The data captured not only the febrile response but the disruption of normal daily temperature rhythms, which were absent for at least 36 hours before largely resolving by day seven. That structure is hard to see in a twice-daily reading. Read Butler et al. (2026).

What Temperature Adds to Clinical Scoring and Body Weight

Clinical scoring, body weight, behavior, and nesting remain essential. They also have known limitations.

Clinical scores vary between observers, and between shifts. Body weight can change late or be confounded by hydration and food intake, and in tumor studies increasing tumor mass can mask loss of normal body mass, so a stable weight does not always mean a stable animal.

Temperature adds a quantitative, observer-independent signal alongside them. The goal is not to replace traditional monitoring but to make it more informative.

Sepsis: Temperature and Humane Endpoints

A 2023 study in Comparative Medicine monitored 80 C57BL/6J mice through cecal ligation and puncture-induced sepsis, combining visual scoring of respiratory status, activity, response to stimulus, and eye appearance with subcutaneous temperature, nesting, and body weight.

Surviving animals generally held relatively stable temperatures. Non-survivors showed a progressive decline. The authors reported that subcutaneous temperature below 32°C could serve as a distinct humane endpoint for this model, offering a quick quantitative evaluation of disease state alongside the clinical scores.

That threshold belongs to that model, that strain, and those housing conditions. It is not a universal number. Applying any threshold to your own protocol requires validation with your veterinary team and IACUC. What the study demonstrates is that validated temperature criteria can support earlier and more objective intervention. Read Ferguson et al. (2023).

Continuous Monitoring Supports the 3Rs

The talk framed the welfare case in terms the AALAS audience works with every day.

• Refinement through less handling. With in-cage systems, readings no longer require restraint or removal from the cage for each measurement.
• Reduction through more data per animal. Longitudinal within-animal trends can improve sensitivity, which may reduce the number of animals a study design requires.
• Refinement through better endpoints. Objective, continuously recorded criteria support earlier humane intervention.

For many study designs, less handling serves the animals and the data at the same time.

Bringing the Measurement to the Cage

Instead of bringing the animal to the monitoring equipment, bring the equipment to the animal.

Animals spend nearly all their time in the home cage. That is where they eat, sleep, interact with cage mates, and follow their circadian cycles. Removing an animal for a measurement introduces handling, restraint, and a change of environment, each of which can influence the very physiology being measured. Home-cage monitoring preserves normal housing, group arrangements, and light cycles, and it continues overnight, on weekends, and between routine checks.

The Microchip

The UCT-2112 temperature-sensing microchip measures 2.1 by 13 mm and is placed subcutaneously by injection rather than surgery. It supplies an individual animal ID and a temperature reading to ±0.1°C at 38°C. The design is passive, so there is no battery to replace and one insertion can stay in place for the animal’s life.

Telemetry remains the right call for continuous arterial pressure or ECG. For temperature alone, the microchip is the lower-impact route. Sensor placement and measurement method both matter when interpreting values or comparing them against core temperature measured another way.

Three Ways to Collect the Data

• Handheld readers: Collect ID and temperature during routine checks or at scheduled experimental time points.
• AnyCage+: Collect individual temperatures automatically as animals enter the antenna’s detection range, tracking each of up to five mice sharing a cage. It scales to 96 cages per system, and antennas clip or mount magnetically without rack modification. VivoTraq handles dashboards, analytics, and real-time alerts.
• Mouse Matrix: Collect temperature, locomotor activity, and zone location through a reader plate beneath the cage, for studies that need high-resolution longitudinal data.

Because each microchip has a unique ID, individual animals remain distinguishable in group housing.

From Reading to Decision

Continuous data is only useful if it reaches someone who can act on it. The talk described the practical vivarium workflow as five steps:

1. Observe. The system collects temperature automatically.
2. Flag. VivoTraq alerts surface unusual patterns without opening every cage.
3. Prioritize. Care staff direct attention to the animals that need it.
4. Intervene. Veterinarians and research teams decide the appropriate action.
5. Document. The temperature history becomes objective documentation for the decision.

This approach is a shift from reactive checks toward proactive welfare management: earlier visibility into the animals that need attention, and fewer cases where a problem is discovered too late.

The Conclusions Worth Taking Back to Your Facility

• Body temperature is a sensitive, objective physiological biomarker.
• Continuous monitoring captures events that intermittent checks miss.
• Temperature is strongest when combined with clinical scoring, weight, behavior, and veterinary judgment.
• Home-cage monitoring supports welfare, refinement, reproducibility, and translational research.

Planning Temperature Monitoring for Your Study?

Tell us about your animals, cages, and measurement schedule, and we will help you work through which readers or home-cage systems fit your needs.

Get in Touch or compare temperature monitoring methods.

Research Cited in the Talk

• O’Brien SW, et al. (2025). Combined treatment with antitoxin and 3,4-diaminopyridine improves survival outcomes after lethal botulinum neurotoxin challenge. Molecular Medicine, 31, 270.
• Ferguson LT, et al. (2023). A Novel Scoring System for Humane Endpoints in Mice with Cecal Ligation and Puncture-Induced Sepsis. Comparative Medicine, 73(6), 446-460.
• Zielinski R, et al. (2023). 2-Deoxy-D-glucose combination with ketogenic diet induces sedation and hypothermia in mice that becomes lethal. Molecular Cancer Therapeutics, 22(12 Supplement), B179.
• Butler MW, et al. (2026). High-elevation adaptation is associated with functional changes in the immune response of deer mice. Proceedings of the Royal Society B, 293(2069), 20253292.