Tail Suspension Test

The Tail Suspension Test is a short behavioral immobility assay that measures the balance between active escape movement and passive immobility while a mouse is suspended by the tail. It is used in rodent research to study coping behavior, and the apparatus records immobility time, latency to immobility, and movement energy from a load-cell transducer or side-view video.

The methods, endpoint definitions, confounds, sample output, and references for the assay are detailed in the research overview below. Request a quote for apparatus configuration and species-specific options.

Request a Quote

Use this apparatus with

The complete Tail Suspension Test workflow

Track behavior

No exact ConductVision tail-suspension page is currently published. Immobility and movement energy are usually captured by a load-cell transducer or a side-view camera; keep automated scoring as a roadmap gap.

Supporting page not yet built

Run protocol

No exact ConductMaze tail-suspension protocol page is currently published. Keep suspension setup, session length, climb-stopper use, and immobility scoring as a roadmap gap rather than linking to a guessed URL.

Supporting page not yet built

Analyze output

Summarize immobility time, latency to immobility, mobility time, and movement energy with quality-control flags for climbing and tracking dropouts.

Tail Suspension Test Calculator ->

Configuration considerations

Common Tail Suspension Test setup decisions

Use these notes to scope species, cohort, tracking, and automation needs. Only verified product or support routes are linked from this section.

This productLoad-cell

Tail Suspension Test Chamber

Enclosed suspension box with a strain-gauge bar and isolated cubicles

Standard configuration for the behavioral immobility assay, suspending the mouse by the tail from a transducer that records movement energy and immobility over a short session.

Quote

Request Quote

BuyableMulti-station

Multi-Station Suspension Rack

Several visually isolated cubicles for parallel testing

Runs several mice at once in separated cubicles so cohorts are tested under matched conditions without visual or social interference.

Quote

View options ->

SpecialtyClimb-stopper

Climb-Stopper Configuration

Tail cylinder or guard that prevents tail-climbing in climbing-prone strains

Adds a climb-stopper for strains such as C57BL/6 that climb their own tails, a behavior that otherwise invalidates the immobility measure.

Quote

Request setup help

§ 1

Introduction

The Tail Suspension Test is a short behavioral immobility assay in which a mouse is suspended by the tail and the balance between active escape movements and passive immobility is recorded. Steru and colleagues introduced it as a rapid mouse method that indexes passive versus active coping during an inescapable mild stressor. 1

The primary endpoint is immobility time, with latency to immobility and movement energy as complementary measures of active coping. The assay is historically used to screen for antidepressant-like activity in rodents; this page treats it strictly as a methods and apparatus resource, and clinical interpretation is out of scope. 1

Suspension height, session length, transducer calibration, body weight, and tail-climbing in climbing-prone strains all change measured immobility. A defensible protocol fixes the session length, calibrates the load cell, uses a climb-stopper where appropriate, and pre-defines the immobility threshold before scoring. 1

§ 2

Methods

2.1 Procedure

Short fixed-length suspension with load-cell or video scoring of immobility, latency, and movement energy.

Pre-test setup

1.Acclimation — Acclimate animals to the room and handling so the first measured session reflects coping behavior rather than acute handling stress.
2.Apparatus calibration — Calibrate the strain-gauge transducer against a known load and confirm the immobility threshold and movement-energy scaling before testing.
3.Climb-stopper decision — For climbing-prone strains such as C57BL/6, fit a tail cylinder or climb-stopper, because tail-climbing removes the animal from suspension and invalidates immobility.
4.Define scoring rules — Fix the session length (commonly six minutes), the immobility definition, and how climbing or tracking dropouts are handled before any data are collected.

Trial sequence

1.Suspend the mouse — Secure the tail to the suspension bar at the standardized height in a visually isolated cubicle and start synchronized recording.1
2.Record movement — Capture immobility time, latency to first immobility, mobility time, and movement energy across the fixed session.3
3.Flag tail-climbing — Mark any tail-climbing episodes; sessions with substantial climbing are excluded or re-run with a climb-stopper.6
4.End and reset — End at the fixed session length, return the animal to its home cage, and clean the cubicle and bar to remove odor before the next subject.
5.Export QC — Review immobility threshold, climbing flags, transducer drift, and body weight before group-level analysis.

Critical methodological constraints

Tail-climbing. Tail-climbing, common in C57BL/6, removes the mouse from suspension and inflates apparent mobility. Use a climb-stopper or exclude affected sessions.6
Session standardization. Suspension height, tape or cylinder method, and session length must be fixed because they change immobility independent of coping state.3
Strain baseline. Baseline immobility differs by strain and sex, so groups must be matched and strain reported.2
Transducer calibration. A drifting or uncalibrated load cell biases immobility and movement-energy readings across the whole session.

2.2 Measurement & Analysis

Core tail-suspension endpoints for coping behavior and quality control.

Immobility Time

Passive coping

Total time spent immobile during the session, the primary endpoint of the assay.1

Latency To Immobility

Coping onset

Time from suspension to the first sustained immobility bout, an index of how quickly active escape gives way to immobility.

Mobility Time

Active coping

Time spent in active escape-like movement, the complement of immobility within the fixed session.

Movement Energy

Struggle intensity

Integrated force or motion magnitude from the transducer, capturing struggle intensity beyond a binary mobile/immobile call.3

Tail-Climbing Flags

Quality-control flag

Count of tail-climbing episodes; high counts invalidate the immobility measure and trigger exclusion or a climb-stopper re-run.6

+ Additional metrics: immobility-bout count, mean bout duration, body weight, strain, session length, and per-cubicle apparatus notes.

2.3 immobility fraction (analysis)

A compact fraction of the session spent immobile.

2.4 sample-size planning

Estimate the N per group needed to detect a literature-anchored effect at the endpoint you plan to report. Override the defaults with your own pilot numbers.

sample-size planning

Estimate the N per group needed to detect a literature-anchored effect at the endpoint you plan to report. Override the defaults with your own pilot numbers.

Stress-exposed vs control mouse in a six-minute session; representative magnitudes from Steru et al. (1985) and subsequent method reviews.1

Control mean (s)Treatment mean (s)Pooled SD (s)

Power (1 - β)Alpha (two-sided)

Cohen's d

1.71

Plan for 10% attrition0%15%30%

N per group at 80% power

Total N

With attrition cushion

At 70% / 90% power

5 / 8

Methods sentence

Using immobility time (s) as the primary endpoint (control μ = 130 s, treatment μ = 195 s, σ = 38 s; Cohen's d = 1.71), a two-sample t-test with α = 0.05 provides 80% power to detect this difference with n = 6 animals per group (N = 12 total; 14 accounting for 10% expected attrition). Pilot magnitudes based on Steru et al. (1985).

Need ANOVA, proportions, paired design, or a power curve? Open in the full Sample-Size Calculator →

Formula: n = 2 · ((z_α/2 + z_β) / d)², where d = |μ₁ − μ₂| / σ. Assumes equal allocation, normality, and homoskedasticity. The attrition cushion inflates total N by 1 / (1 − dropout); confirm with your IACUC.

§ 3

Results

Aggregate publication data, sample apparatus output, and recent findings from the live PubMed feed.

3.1 Publication trends

PubMed volume and co-occurring behavioral methods for tail-suspension studies.

3.2 Sample apparatus output

Representative output from a six-minute tail-suspension session scored from a load-cell transducer.

Table 1 · Per-animal EPM scoring output

Download sample CSV →

Animal	Group	Immobility	Latency	Movement energy	Immobility fraction
TST-001	Control	118 s	64 s	0.71	32.8%
TST-002	Control	132 s	58 s	0.66	36.7%
TST-003	Control	126 s	61 s	0.69	35.0%
TST-004	Stressed	198 s	34 s	0.41	55.0%
TST-005	Stressed	205 s	31 s	0.38	56.9%
TST-006	Stressed	189 s	37 s	0.44	52.5%

Synthetic example for illustration only. Pair immobility with latency, movement energy, strain baseline, and tail-climbing flags before interpreting coping differences.

3.3 Recent findings (live PubMed feed)

Auto-curated weekly. Last refreshed 2026-06-12. Live

Jun 2026Source note
Tail-suspension methods continue to emphasize climb control and fixed session length.
Static methods note aligned with Steru et al. (1985), Cryan et al. (2005), and Mayorga & Lucki (2001).
Review tail-suspension studies for a fixed session length, a documented climb-stopper or tail-climbing exclusion rule, a calibrated transducer, and a pre-specified immobility threshold before interpreting group differences.
Methods overviewReproducibility
Jun 2026Source note
Tail suspension as one assay in a coping battery: pair with forced swim and activity measures.
Static methods note aligned with Can et al. (2012) and Castagne et al. (2011).
Immobility is one signal of passive coping. Interpretation is most defensible when reported with latency to immobility, movement energy, and an independent locomotor measure in the same cohort.
Coping batteryActive vs passive coping

View all 2180matching papers on PubMed ->

§ 4

Discussion

Limitations of the paradigm, methodological caveats, and current directions.

4.1 Common confounds

Variables that shift Tail Suspension Test results independent of anxiety state.

Tail-climbing

Climbing-prone strains climb their own tails, leaving suspension and inflating apparent mobility. A climb-stopper or session exclusion is required.

Session standardization

Suspension height, attachment method, and session length change immobility independent of coping state and must be held constant.

Strain and sex

Baseline immobility varies by strain and sex, so groups must be matched and the background reported.

Transducer calibration

An uncalibrated or drifting load cell biases immobility and movement-energy readings across the session.

Handling and acclimation

Acute handling stress before testing can shift early-session behavior and should be standardized across groups.

Confound checklist

Tick the confounds your protocol addresses, then export a methods-paragraph blurb you can paste into your manuscript.

Tail-climbing. Climbing-prone strains climb their own tails, leaving suspension and inflating apparent mobility. A climb-stopper or session exclusion is required.
Session standardization. Suspension height, attachment method, and session length change immobility independent of coping state and must be held constant.
Strain and sex. Baseline immobility varies by strain and sex, so groups must be matched and the background reported.
Transducer calibration. An uncalibrated or drifting load cell biases immobility and movement-energy readings across the session.
Handling and acclimation. Acute handling stress before testing can shift early-session behavior and should be standardized across groups.

Preview exported markdown

## Tail Suspension Test — methods controls

Confounds controlled in this protocol:

- **Tail-climbing.** Climbing-prone strains climb their own tails, leaving suspension and inflating apparent mobility. A climb-stopper or session exclusion is required.
- **Session standardization.** Suspension height, attachment method, and session length change immobility independent of coping state and must be held constant.
- **Strain and sex.** Baseline immobility varies by strain and sex, so groups must be matched and the background reported.
- **Transducer calibration.** An uncalibrated or drifting load cell biases immobility and movement-energy readings across the session.
- **Handling and acclimation.** Acute handling stress before testing can shift early-session behavior and should be standardized across groups.

4.2 Construct validity caveats

The Tail Suspension Test is a research methods model of passive versus active coping, not a clinical instrument, and clinical interpretation is out of scope for this page. Results are strongest when session length, climb-stopper use, immobility threshold, and strain are fixed before testing and immobility is reported with latency and movement energy. 1

4.3 Special considerations

How does it compare to the forced swim test?

Both index passive versus active coping, but tail suspension avoids water, hypothermia, and swimming-ability confounds. It is mouse-specific and sensitive to tail-climbing, whereas the forced swim test applies across rats and mice.

Do I need a climb-stopper?

For climbing-prone strains such as C57BL/6, yes. Tail-climbing removes the animal from suspension and invalidates immobility, so a climb-stopper or documented exclusion rule is needed.

What session length should I use?

A fixed short session, commonly six minutes, is standard. Whatever length is chosen must be held constant across all groups and reported.

4.4 Current directions

Quarterly editorial review of emerging Tail Suspension Test methodology. Q2 2026

Methods

Movement-energy reporting

Reporting integrated movement energy alongside binary immobility gives a more graded read of active coping than immobility time alone.

Emerging

Automated load-cell scoring

Transducer-based scoring reduces observer bias and captures latency and movement energy consistently across cohorts.

Methods

Climb-control standardization

Documenting climb-stopper use and tail-climbing exclusion is increasingly expected for strain-comparable immobility data.

Emerging

Cross-assay coping batteries

Tail suspension is paired with the forced swim test and activity measures to separate coping behavior from general locomotor differences.

§ 5

References

6 selected methods and validation references for Tail Suspension Test.

Steru L, Chermat R, Thierry B, Simon P. The tail suspension test: a new method for screening antidepressants in mice. Psychopharmacology (Berl). 1985;85(3):367-370. doi:10.1007/BF00428203
Cryan JF, Mombereau C, Vassout A. The tail suspension test as a model for assessing antidepressant activity: review of pharmacological and genetic studies in mice. Neurosci Biobehav Rev. 2005;29(4-5):571-625. doi:10.1016/j.neubiorev.2005.03.009
Can A, Dao DT, Terrillion CE, Piantadosi SC, Bhat S, Gould TD. The tail suspension test. J Vis Exp. 2012;(59):e3769. doi:10.3791/3769
Castagne V, Moser P, Roux S, Porsolt RD. Rodent models of depression: forced swim and tail suspension behavioral despair tests in rats and mice. Curr Protoc Neurosci. 2011;Chapter 8:Unit 8.10A. doi:10.1002/0471142301.ns0810as55
Bai F, Li X, Clay M, Lindstrom T, Skolnick P. Intra- and interstrain differences in models of behavioral despair. Pharmacol Biochem Behav. 2001;70(2-3):187-192. doi:10.1016/s0091-3057(01)00599-8
Mayorga AJ, Lucki I. Limitations on the use of the C57BL/6 mouse in the tail suspension test. Psychopharmacology (Berl). 2001;155(1):110-112. doi:10.1007/s002130100687