Field Judging Wild Sheep

IN PARTNERSHIP WITH THE BOONE AND CROCKETT CLUB

THE OPPORTUNITY TO HUNT A WILD SHEEP RAM IS SPECIAL. CONSEQUENTLY, THE PREVAILING OPINION AMONG SHEEP HUNTERS IS THAT ALL RAMS ARE SPECIAL. THIS REFLECTS OUR RESPECT FOR THIS ICONIC SPECIES AND HOW RARE IT CAN BE TO HUNT THEM.

 

While "all rams are special" is a true statement, it doesn't help much in determining the right ram for you to take once you're behind glass on a mountainside. With few exceptions, those lucky enough to win or draw a sheep tag are looking for the oldest and biggest legal ram they can find.

 
For the guided hunter, your guide will be a reliable source on what to expect regarding the quality of rams in the area you're hunting. They are invaluable when aging a truly mature ram and judging the size and the score. For the do-it-yourself hunter, all of these evaluations fall on you. In either case, having the skills to judge a ram in the field accurately can be just as important as any other preparations you make.
 
This guide is intended to give you the tools—including tips from the experts—to judge North America’s wild sheep confidently.
 

Examples of mature rams for each of the four North American wild sheep,  in order of appearance – Dall's sheep, Stone's sheep, Rocky Mountain bighorn, and desert bighorn.

SHEEP OVERVIEW 
There are four native North American wild sheep species, classified into two categories: thinhorns (Dall’s and Stone’s sheep) and bighorns (bighorn and desert bighorn sheep). All rams are scored the same way for the Boone and Crockett Club's (B&C) records program, the scoring system referenced throughout. With a few subtle differences, the method for judging wild sheep in the field for trophy quality is the same among the four species.
 
Sheep are also relatively easy to score under the B&C system, with scores consisting of the total length of both horns combined with mass measurements from each horn base, plus three additional quarter mass or circumference measurements. Field judging, therefore, comes down to looking at horn length and mass.

  

You can easily see the annuli on the bighorn pictured above/left, which aids in aging a sheep. Being able to study a sheep like this Stone's ram through a spotting scope is an added bonus.

In wild sheep, horn size is generally a direct reflection of age, meaning older rams will have more mass. However, the potential for horn size can vary within the same species but in different locations, as well as the genetics and habitat conditions in those locations. In other words, the top-end mass in one sheep population could be only the average mass for a population in a different area. Knowing as much as possible about the current populations where you will be hunting will help your evaluations.

Sheep are among the few big game species that can be aged accurately through a spotting scope given the right conditions. Quality optics combined with good side views of the horns will often allow hunters to count the number of annular growth rings (annuli) on the horns. While exceptions exist, a true trophy sheep will almost always be 9 to 13 years old.

Genetics certainly play a role in horn size, but habitat conditions and stress-free living can contribute as much as genetics. According to B&C, on average, mass makes up 55-60 percent of the total score of all record book bighorns. For thinhorns, this percentage is less (50-55 percent) of the score because, as their name suggests, thinhorns carry less mass. 
 
Besides age, other factors that are worth noting come into play, starting with species. Thinhorns will not score as high as bighorns due to less horn mass. In addition, the mountain range where a species is hunted is another factor. With that knowledge in hand, here are some tips once you have eyes on rams.
 


First, the adage, "they always look bigger going away," certainly holds true with sheep. It is never a good idea to make a judgment when the ram is facing away. Any mature ram will look much bigger than it is when viewed from behind. Full frontal and side views are needed to assess a ram's age, length, and mass accurately. 
   

Judging the Curl 

Record book-caliber rams will almost always present as a square-box horn configuration when viewed from the front—the horns extend high out of the head and away from the ears and then drop down below the jawline. On Dall's and Stone's sheep, the horns will come up and flare out again, which gives the box an even wider appearance. This heavy box look is what gives a record-book ram that "wow" factor when first viewed from a spotting scope. 
 
Regardless of the species, the lower curve of the horn of a trophy-quality ram will almost always drop below the jawline. The deeper the curl, the more likely the horns meet or exceed the current All-time record book minimum entry score for that species. In instances where the bottom line of the descending horn on a full-curl ram fails to drop below the bottom line of the jawbone, the ram will seldom possess the length and mass needed to meet the minimum score. In the case of thinhorns, such trophies may readily measure on the curl from 36 to 39 inches, but they are unlikely ever to measure 40 inches or better. In all species, the weight (mass) of the horn on such a ram will rarely carry far enough to produce good second- and third-quarter circumference measurements. Many are indeed beautiful, even magnificent trophies, but they will not score high.

Horns that dip down below the jawline is a box to check when looking for a high-scoring ram. Combine above-average mass with the horn length that comes with this lower horn curve, and you will have the makings of a book ram.

For Stone's and Dall's sheep, assuming that the bottom of the curl approximates the lower jawline and rises to the level of the nostril, these horns are likely to run about 35 inches long. If the horns extend 2-3 inches above the eyes, the horns should be in the 37- to 38-inch range. Thinhorns with unexceptional mass measurements and horn lengths in the 35-inch range will score around 145 B&C points, while rams with similar mass in the 37- to 39-inch range will score 150-160. Neither would represent a record-book trophy.

With bighorns, the curl described above would likely be 1-2 inches shorter because many bighorns have close, tight curls. Again, as bighorns, these would not make the record book. To make the record book, a bighorn almost always requires a horn in which the bottom of the curl approximates the rear base of the lower jawline, and the horn tips make a full curl or more. From the front, bighorns with outstanding length will generally "tip-up" instead of flaring out like a thin horn.
 

Judging Mass 

The rest of the score depends on the mass measurements from the horn bases and three additional quarter measurements. These are referenced on the official score sheet as the "D" (circumference) measurements.

The beginning sheep hunter often needs to remember the importance of horn mass in the overall calculation of the final score. For a given apparent length of the horn, one already broomed will carry more weight and produce higher circumference measurements for the second and third quarters than the horns on which the lamb tips (year one annuli) are still present. Strong second- and third-quarter measurements are essential for a ram to meet the minimum entry requirements.

Judging the base circumference in the field, especially from a long distance, is the most challenging task for the beginning sheep hunter. There is no hard and fast rule for determining base size, and many hunters have been fooled using formulas that involve the space between the ram's horns or how close the base starts to the ram's eye. Though both can be helpful as a reference, it is often easier to judge mass at the second quarter and then work back to the base. Many experienced guides use a formula (base minus 1 inch) for the first-quarter measurements, 2 inches for the second quarter, and 5 or 6 for the third-quarter measurements on bighorns. For thinhorns, the guidelines are base minus 1, 3, 6, or 7 inches since they tend to "thin" out faster by name and nature. 

 

There are eight mass measurements taken on a ram–four per side. Base circumferences are tricky to judge in the field. Mass at the base continues out to the second and third circumference measuring points can be a ram worthy of your tag. This is what the expression “carrying mass all the way out” means.

Desert Rams 
Desert sheep of the subspecies mexicana, as found in southern Arizona, New Mexico, and the Mexican states of Sonora and Coahuila, seldom exhibit the "argali" flare, often found in thinhorns and sometimes found in bighorns and the nelsoni sub-species of desert sheep. In other words, the horns do not tip in and then flare out at the tips. Many desert sheep also lack the close curl characteristic of the bighorns. Instead, their horns are more inclined to sweep out and down. It is not uncommon to find a desert ram with horns whose curl bottom is as much as two inches below the jawbone line. Frequently, such horns are not badly broomed and may or may not carry their mass out to the tips. As a rule, a mature desert sheep can show a horn base circumference even larger than that of a bighorn of the same age. It is vital to get a good side view of such a ram to judge the mass of its horns through the second and third quarters.



The criteria for judging the horn length on thinhorn sheep does not necessarily apply here. However, if you are looking head-on at a mature desert ram with the bottom of the curl lower than the base of the jawline and the tips of the horns approximating a full curl, you may be looking at a record-book sheep. When the tips are broomed to the point that you are looking at something between a strong three-quarter- and seven-eighths curl,  you are probably looking at a length of the horn of about 36 inches. A really heavy 36-inch curl on this particular sheep can readily make the record book minimum entry score of 168 for desert sheep.

SUMMARY

As with the field judging of any big game animal, proficiency takes time and practice. Sheep, though, are some of the easiest trophies to judge accurately once a hunter develops the basic skills of determining length and mass. A real trophy ram is instantly recognizable by anyone familiar with wild sheep. Pass up the shot if you hesitate about whether the trophy is record-class. Inevitably, it will fall short.
 

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ADDITIONAL INFORMATION

B&C and P&Y Minimum Entry Scores
 

• DALL'S SHEEP – 160 B&C points (rifle) and 120 P&Y points (archery) 
• STONE'S SHEEP – 160 B&C points (rifle) and 120 P&Y points (archery) 
• DESERT BIGHORN – 165 B&C points (rifle) and 120 P&Y points (archery) 
• ROCKY MOUNTAIN BIGHORN - 175 B&C points (rifle) and 140 P&Y points (archery)