Autohaemorrhaging

Horned lizard showing evidence of autohaemorrhaging

Autohaemorrhaging, or reflex bleeding, is the action of animals deliberately ejecting blood from their bodies. Autohaemorrhaging has been observed as occurring in two variations.[1] In the first form, blood is squirted toward a predator. The blood of these animals usually contains toxic compounds, making the behaviour an effective chemical defence mechanism. In the second form, blood is not squirted, but is slowly emitted from the animal's body. This form appears to serve a deterrent effect, and is used by animals whose blood does not seem to be toxic.[1] Most animals that autohaemorrhage are insects, but some reptiles also display this behaviour.[2]

Some organisms have shown an ability to tailor their autohaemorrhaging response. Armoured crickets will projectile autohaemorrhage over longer distances when attacked from the side, compared to being attacked from an overhead predator.[3]

  1. ^ a b Iftime, Alexandru; Iftime, Oana (January 2014). "Thanatosis and autohaemorrhaging in the Aesculapian Snake Zamenis". Herpetozoa. 26 (3–4): 173–174 – via Zobodat.
  2. ^ Bateman, P. W.; Fleming, P. A. (2009). "There will be blood: autohaemorrhage behaviour as part of the defence repertoire of an insect". Journal of Zoology. 278 (4): 342–348. doi:10.1111/j.1469-7998.2009.00582.x. ISSN 1469-7998.
  3. ^ Bateman, Philip W.; Fleming, Patricia A. (2012-04-26). "Signaling or Not-Signaling: Variation in Vulnerability and Defense Tactics of Armored Ground Crickets (Acanthoplus Speiseri: Orthoptera, Tettigoniidae, Hetrodinae)". Journal of Insect Behavior. 26 (1): 14–22. doi:10.1007/s10905-012-9329-5. ISSN 0892-7553. S2CID 18599346.