Study
Snake constriction rapidly induces circulatory arrest in rats
Boback, Scott M.; McCann, Katelyn J.; Wood, Kevin A.; McNeal, Patrick M.; Blankenship, Emmett L.; Zwemer, Charles F.
Journal of Experimental Biology, 2015
Anaesthetised rats were instrumented to record arterial and venous blood pressure, heart electrical activity and blood chemistry, then offered to boa constrictors. The measurements ran throughout constriction, so the sequence of physiological failure could be observed rather than inferred from the outcome.
- Studied in
- Boa constrictor, Rattus norvegicus
- Sample size
- 24 anaesthetised rats subjected to constriction
Arterial pressure halved within about six seconds of constriction beginning, while venous pressure rose sharply. Heart electrical activity became disordered within a minute and blood potassium rose steeply. Circulatory arrest preceded any plausible time course for suffocation.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Constriction kills by rapidly arresting circulation — shutting off blood supply to the brain and heart — rather than by preventing breathing.
How NatureHQ reads it
Everyone is taught that constrictors suffocate their prey, and the measurement says otherwise: the animal is dead from circulatory failure long before a lack of air could account for it. This is a good example of a mechanism that was assumed for a century because the outcome was obvious and the middle was never instrumented. It also reframes the behaviour — a constrictor is not squeezing until breathing stops, it is applying pressure the circulatory system cannot work against, which is why the process is quick.
- Anaesthetised prey cannot struggle, which may alter the time course.
- One constrictor species and one prey species; other constrictors differ in size and coil mechanics.
- Measurements are of prey physiology and say nothing directly about what the snake detects or controls.
Instrumenting the inside of a constriction
Does a constrictor actually kill by suffocation, as everyone has assumed for a century?
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: The Company of BiologistsPublished by The Company of Biologists.
This reference was resolved automatically against Crossref on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-11.