Autohaemorrhaging

Autohaemorrhaging is a biological phenomenon where an organism intentionally ruptures its own blood vessels, causing blood to be expelled from the body. This is often used as a defensive mechanism against predators. The term is derived from the Greek words auto meaning self, and haemorrhage meaning to bleed profusely.

Overview

Autohaemorrhaging is observed in a variety of animal species, including some types of lizards, insects, and sea cucumbers. The blood released during autohaemorrhaging can contain toxins or other substances that are harmful or distasteful to predators. In some cases, the blood is also brightly colored, which can serve as a visual warning signal.

Mechanism

The mechanism of autohaemorrhaging varies between species. In some cases, the animal has specialized structures or organs that allow it to rupture its own blood vessels. For example, the Texas Horned Lizard has a network of blood vessels around its eyes that it can rupture to squirt blood at predators. In other cases, the animal may simply exert pressure on its body to force blood out through its skin or other body openings.

Ecological Significance

Autohaemorrhaging can be an effective defense mechanism, but it also comes with costs. The loss of blood can weaken the animal and make it more vulnerable to other threats. Furthermore, the use of toxins in the blood can also have negative effects on the animal's own body. Despite these costs, autohaemorrhaging is thought to have evolved because the benefits of deterring predators outweigh the costs.

See Also

• Antipredator adaptation
• Reflex bleeding
• Autotomy