Observation of llamas living on the altiplano and in use as pack animals demonstrates the function of their fiber and the versatile protection they enjoy.
The altiplano is an extremely high (+/- 3500 m.=+/- 12,000’) desert plain with daily year-round temperature fluctuations of 40o-50o F. Llamas thrive in this climate. Our llamas here in Colorado tolerate seasonal extremes of -25oF in winter to 100oF in the summer while the daily fluctuations are typically around 30o-40o F. On days spent packing and working, llamas produce sweat that vaporizes and wicks away through the fleece. Dampness under the saddle pad that impedes moisture dispersion is the only evidence of liquid perspiration. Their packing performance is unaffected whether in sub-zero mountain temperatures or +95oF desert temperatures.
Llamas wear the same fleece in these varying conditions and readily tolerate either extreme. This demonstrates spatial insulation and loft play a minor role. Otherwise, the layers that protect them at the low temperatures would be too warm at the upper temps and vice versa. The conclusion is that the thermoregulation results from a constantly maintained level of water vapor in their fiber that holds latent heat during cold conditions and dissipates excess moisture and its latent heat as temperatures and exertion rise.
Since we started wearing llama fiber, we have noted we travel lighter and better prepared for weather extremes commonly encountered on the trail. We now enjoy the same comfort and versatility as our llamas because we understand and employ the advantages their fiber provides. These principles govern our clothing designs and fabric development. We use 100% llama fiber in our products including linings and pocket bags and recognize blending llama with synthetic fibers causes serious compromise. We advocate careful consideration in selecting and sequencing layers when layering with garments made from other fibers to avoid diminishing or impeding the performance of Altiplano garments. Personal comfort is optimized when llama fiber is allowed to perform unhindered by the low performance fibers commonly used in today’s clothing industry.
Llama fiber’s ability to maintain a constant water vapor content, allows it to provide a constant temperature and moisture level within the personal atmosphere of their fleece, providing dependable protection in all conditions.
Llama fiber is hygroscopic. It can attract water vapor molecules from the surrounding atmosphere and hold them on the surface of the fiber as dispersed, individual molecules. Llama fiber holds these molecules by adsorption, a process that utilizes passive, non-molecular bonds that are easily broken. Adsorption differs from absorption, a process which bonds groups of water molecules (liquid) by active molecular bonds to the absorbing fiber, requiring heat to be broken and dispersed.
A fiber’s hygroscopic properties or level of adsorption is expressed as “moisture regain” (MR). This value is determined by a laboratory test that weighs a sample of oven dried fiber, holding no adsorbed water molecules. After exposure to the atmosphere, it is reweighed. The difference in the dry and exposed weights is the result of hygroscopic moisture adsorption from the surrounding air. This weight difference, expressed as a percentage of the dry weight, is the (MR) moisture regain value.
This moisture regain value, can fluctuate a bit depending on air temperature and relative humidity, but the average value has a predictable range. The MR for llama fiber is +/- 27%, a high value in comparison to other fibers. Natural fibers, particularly animal fibers, tend to have higher MR values than plant fibers and significantly higher values than synthetic fibers. Atmospheric moisture content fluctuates, while the moisture carrying capacity of llama fiber is constant. In low humidity conditions it will retain moisture rather than give it up to the drier air. It will even pull water vapor from the drier air to hold its constant level of adsorbed moisture. In high humidity, the fiber will not hold more moisture, but will release excess moisture to the outside air.
When wearing llama fiber (llamas or people) and increased physical activity or air temperature cause perspiration, the liquid perspiration evaporates into water vapor, cooling the skin surface. The vapor migrates into the covering fiber which causes an increase in water molecules in turn raising the moisture content above the MR level. Water molecules then migrate to the surface of the fleece and dissipate into the atmosphere to reestablish the normal moisture content. Llama fiber is noted as having exceptional moisture wicking properties and its high MR is the reason.
MR also indicates the warmth or insulating capacity of a fiber. The clothing industry has traditionally attributed the insulating capacity of various textiles to the dead air space and loft they create. This is a factor, but it is minor by comparison. Llama fiber does enjoy an advantage in this measure of function because it is medullated or hollow.
The major reason llama fiber has greater warmth is its high MR value. It’s ability to hold a constant level of water vapor creates a heat reservoir by virtue of the latent heat of vaporization contained in the adsorbed water molecules. This allows conservation of a body’s generated heat as well as add solar heat contained in the surrounding atmosphere’s water vapor.
Understanding the properties of water vapor and its role in regulating the earth’s atmosphere is necessary to understand how llama fiber works.
The Hydrologic Cycle Always Has Been, and Always Will Be, the Earth’s Most Efficient Method of Collecting and Distributing Solar Energy.
Water vapor is a foundational part of the hydrologic cycle that creates the earth’s protective atmosphere and makes the planet habitable. Water vapor is the gaseous state of water and is composed of water molecules that are dispersed because of the heat energy they carry. One gram of liquid water caries 540 calories of heat at the point of conversion to water vapor. This heat is called “the latent heat of vaporization” and is held by the water molecules as long as they are dispersed in vapor form in the air.
A cooling effect is produced in the earth’s atmosphere when surface water absorbs the sun’s heat until it vaporizes and disperses into the atmosphere. Water vapor released by plant transpiration produces the same cooling effect. The water molecules carrying latent heat of vaporization, migrate from the earth’s surface atmosphere to its upper atmosphere. The vapor cools and condenses to form clouds that provide varying degrees of shade from the sun’s powerful rays and absorb additional heat from the sun. Dissipation of heat from the molecules in the water vapor causes them to condense back into liquid precipitation and begin the cycle again. The extreme high temperatures from direct sunlight and the extreme cold temperatures that result at night in its absence are moderated by the thermoregulating actions of water vapor present in the earth’s atmosphere.