When do deer shed their antlers and why does it bleed when deer shed antlers?

Deer bleeds when shedding antlers| Role of antlers in herbivores|Is is painful for deer to shed antlers?

We may have seen a deer in a jungle or wildlife park especially a male one with prominent antlers but do we know that these antlers have an important role in the life cycle of these herbivores. One more misconception people have is that horns and antlers are quite similar in their role but it is not the case.

 These horns in an herbivore remain and grow with the animal throughout its life whereas antlers grow and shed in cycles every year. Antlers are nothing but bony structures growing from the frontal bone structure of the skull starting from a padded skin protrusion. 

                                            

Shedding of velvet skin on antlers   
Image Source-  Google | Image by - Flickr

In the developing stage, these are covered by thin skin called velvet. In the spring season development of antlers begins in deers with the development of padded circular skin which ultimately grows into antlers. In the developing stage, as the antlers grow for a period of 3 to 4 months, velvet formation takes place which is a thin skin carrying cells and veins to carry nutrients and minerals to the antlers to grow. 

This period of growth takes place till antlers have gained their size and eventually right before the mating season, this velvet shed which causes bleeding in the antlers. This phenomenon is usually known as “bleeding antlers”. 

Since the velvet carries veins and blood vessels allowing the blood flow, velvet shed causes bleeding which may seem painful for the deer but it is not since the bone inside has hardened, calcified, and turned granular thereby cutting any blood supply further and hence no sensation of pain. 

This hardened bone is the dark-coloured antler that is associated with males. Shedding of velvet can be seen in deer when they rub their antlers against the bark of trees and bushes. These antlers are prominent in males but in the case of Caribou reindeer, antlers grow in both males and females. Whereas in the case of Chinese Water deer and Musk deer, no antler is seen even in the males (Source-https://www.wildlifeonline.me.uk/). 

                                                   

Bleeding caused during antler shed     
Image Source-  Google | Image by - Flickr

Once these antlers attain their maximum size and become hard and granular in structure, it is usually the peak of mating season wherein these antlers are used by males in fights to win over females and establish their dominion. Sometimes these fights result in premature breakage of these antlers and the one which has its antlers intact wins. It is a tool to show strength among males. 

After the completion of mating season, before the onset of winters, the testosterone level in males decreases, and the osteoclast layer of cells at the connection of antlers to the frontal skull begins to absorb calcium from the antlers making them weak and more granular with a honeycomb structure. 

Ultimately these become weaker and cracks at the junction with the skull where it bleeds and results in shedding of antlers. This development and shed cycle of antlers is cyclic concerning seasonal patterns and occurs every year. But this phenomenon also depends on the health, age and physical condition of male deer.

Deer bleeds when shedding antlers| Role of antlers in herbivores|Is is painful for deer to shed antlers?