#i'm too squeamish to let my rats swim to exhaustion

[unsupervisedrat]

How Long Can Rats Swim

PETA used to complain about the unethical nature Behavioral Despair Tests, where a rat, after being subject to some procedure, is placed in water to swim to exhaustion. The time to exhaustion is used to gain a relative measure of how easily the rat "gives up", after the procedure, to gain some inside in the procedure's mood altering abilities.

The test is terminated at 15 minutes for rats [0].

(Pictured: various claims that rats can swim for 3 days).

If a rat can swim for 3 days, how would it ever give up in under 15 minutes?

Some cursory research [1][2] shows that, rats swim to exhaustion in between 8-25 minutes, with huge variance.

🥁 (Pictured: drum roll) It turns out that, when researchers force a rat to swim to research exercise, sometimes the rat will simply learn to float by fluffing themselves! This expends basically no energy on part of the rat

Rat swimming movements create water turbulence which traps air bubbles in their fur increasing buoyancy . This process may be so effective that they fall asleep as they float in thewater and rats learn to do this so as to float with very little movement. VO 2 measured in floating rats is close to that measured during resting conditions on a motorized treadmill and therefore represents an egligible exercise stressor.

tldr:Rats fluff themselves up to float and relax instead of swim [0] https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/forced-swim-tes

[1] Hardin, D. H. (1968). Reliability of Selected Swimming Endurance Tests for Laboratory Rats. Research Quarterly. American Association for Health, Physical Education and Recreation, 39(2), 405–407.

[2] Beaton, J. R., & Feleki, V. (1966). THE EFFECT OF NUTRITIONAL STATE ON ABILITY OF THE RAT TO SWIM TO EXHAUSTION. Canadian Journal of Physiology and Pharmacology, 44(4), 597–603. doi:10.1139/y66-076 

[3] https://journals.physiology.org/doi/full/10.1152/ajpheart.00697.2019