Why your blood is red, but some creatures’ may be green or purple

HAVE you ever wondered why your blood is red?

Biodiversity and conservation biology senior lecturer Adriaan Engelbrecht explained that haemoglobin is responsible for the red colour of blood and it carries oxygen in our circulatory system, transmitting it through the body. Blood is needed for all specific organisms’ organs to operate properly; without it, no organism can survive.

However, there are varieties of animals who bleed colours other than red. Blood is available in a number of shades, including green, blue, purple and sometimes colourless.

“There are a group of fish in the Antarctic with colourless blood, they are called ice fish because they live so deep in the ocean they do not need haemoglobin to carry oxygen around in their systems. They have instead colourless blood with lots of antifreeze proteins in it to protect them from the cold,” said Engelbrecht.

Creatures that we come across every day, such as spiders, have blue blood. Animals that also have blue

(Notothenioidei),

blood include octopus and squids.

Blood plays a critical role in our body as it is our life force.

“The five critical functions of blood in our body include transporting oxygen and nutrients to the lungs and tissues, forming blood clots to prevent excess blood loss, carrying cells and antibodies that fight infection, bringing

waste products to the kidneys and liver, which filter and clean the blood, and regulating body temperature,” said Engelbrecht.

He added that the more we know about blood and how it functions with its different functionalities, the better it is for us to develop new drugs and better drug delivery methods.

| REUTERS SOME creatures, like octopuses, have blue blood.

Human blood is red because it contains haemoglobin.