Why do deer rub the bark off trees? Before we answer that question, we need a brief introduction to antlers. Male deer shed and grow a new set of antlers every year. Each year growing a fresh set typically larger then the previous. The cycle begins in the late spring. Throughout the growing stage, the antlers are rich in blood and covered in a hair like material commonly known as velvet. During this period the antlers are susceptible to damage such as cuts and bruises, similar to their skin. Late in the summer, the growth cycles stops and the antlers start to mineralize or harden. The fleshly velvet dries into a fluffy fuzz. If left alone, this new fuzz would fall off on its own.
Here is where we begin our lesson in deer rubs.
Late Summer (August / September)
Antler growth stops in the late summer months. Around this time rubs may begin to appear as the deer speed up the natural process of velvet shedding. While rubs at this early stage are not as common as later in the year. Stubborn velvet may need additional help with removal.
Fall (October / November)
In the fall months, the rubs start to change. During the breeding season, also known as the rut, the tubular apocrine sudoriferous glands are activated. These glands produce a sent unique to each deer. It is believed that deer use this scent to let other know they are in the area or reply to deer from a previous rub.
Deer will rub their antlers, top of their head, and other parts of their body on the trees to leave their calling card for other to follow.
Tree size vs. deer size
It is commonly assumed the bigger the rub the bigger the deer. Research shows, my own included, little deer can make big rubs. Look at the many trail cam pictures of fork horns tearing up trees big and small.
A better indicator of big deer is the height of the rub. Taller rubs indicate bigger deer, for obvious reasons.
Rub lines are used like maps for locating deer. Find one rub, then look around, another one is typically a short distance away. Keep moving down the line until a complete path is mapped out. Traditional rubs are used over and over by deer in the area. For hunters, these lines help determine hunting locations during the appropriate seasons.
Lines may change, don’t rely on previous years for the deer to return. Look for fresh rubs indicated by clean, wet, or fleshy rub areas. Old rubs will be dirty or darker brown as the tree heals itself.