A Fresh Start for Burros

Wild horses and burros are defined by federal law as unbranded, unclaimed, free-roaming horses or burros found on public lands in the United States.  Today, the Bureau of Land Management protects and manages wild horses and burros in balance with other public resource values on 175 herd management areas across 25.6 million acres of public lands. Most wild horses and burros living today are descendants of animals that were released or escaped from Spanish explorers, ranchers, miners, the U.S. Cavalry and Native Americans. 

 Wild burros roam rangeland in California, Nevada, Arizona, Utah and Oregon. Pursuant to the Wild Free-Roaming Horses and Burros Act, the BLM and U.S. Forest Service manage wild horses on subsets of public lands where the animals were found upon passage of the Act in 1971.  These areas are known as Herd Management Areas.

 Wild horses and burros are known for their sure-footedness, strength, intelligence and endurance.  With kindness and patience, these animals can be trained for many uses.    

A freeze mark is a permanent identification marking applied to wild horse or burro by the Bureau of Land Management. Every wild horse or burro removed from public lands by the BLM receives a freeze mark in addition to a microchip.

For adopters and owners, the freeze mark is often more than just a number—it’s a point of pride. It represents the animal’s history and connection to America’s public lands, and many people see it as a badge of honor that reflects their role in giving a wild horse or burro a new home.

The BLM uses the International Alpha Angle System to create freeze marks. This system consists of unique symbols representing numbers, ensuring that every animal has a distinct identifier.

The freeze mark is applied to the left side of the animal’s neck using a cold-marking process. A specially designed iron is chilled in liquid nitrogen and pressed against the skin. The extreme cold changes the pigment-producing hair follicles, causing the hair to grow back white. This makes the mark gentle to apply, permanent, and easily visible for the life of the animal.    

1. Locate the freeze mark. 
   Look on the left side of the horse or burro's neck. Sometimes the hair may need to be clipped or shaved for better reading. Taking a clear photo of the freeze mark and adjusting the contrast may also help. 
2. Identify the first symbol
   Resembling an oversized "U," this is the U.S. Government brand, indicating the animal was gathered by the BLM. 
3. Decode the birth year and registration number
   Use the Alpha Angle System chart to compare each symbol that comes after the "U" and determine the corresponding number.
   The first two symbols (stacked vertically) represent the last two digits of the animal’s birth year. For example, if the symbols correspond to “1” and “9,” the animal was born in 2019. The remaining symbols form a unique six-digit registration number assigned to the animal, including the four-digit tag number the animal wears around its neck at BLM facilities.