periods. Such food can be regurgitated 
and chewed while the animal is at 
rest, as in the familiar cud chewing 
of domestic cows. The primary ad- 
vantage of the rumen is that it allows 
an animal to subsist on relatively low- 
quality food by increasing the effi- 
ciency of the digestive system. 
Mineral licks are another important 
aspect of the mountain goat’s ecology. 
The animals have a craving for salt, 
which seems to peak in late spring 
and early summer. This peak coincides 
with the time in which they are mak- 
ing a transition from low-quality win- 
ter forage to newly emergent vege- 
tation. Physiological studies have 
shown that an ungulate’s ability to 
retain sodium — an element necessary 
for many bodily functions — is influ- 
enced by diet. Ingestion of newly 
emergent and highly succulent vege- 
tation increases the loss of sodium in 
the feces, and the animals may com- 
pensate for this deficiency by consum- 
ing the substance directly. More re- 
cently, however, studies of the chem- 
ical composition of natural mineral 
licks suggest that sodium may be a 
relatively rare element, and that un- 
gulates may actually be seeking in- 
organic sulfur in the form of sulfates. 
These substances are converted in the 
ruminant’s digestive system into 
amino acids, such as cystine, which 
are essential for hair growth and lac- 
tation. 
There are no natural mineral licks 
in the Olympic Mountains that are 
known to be used by goats, but the 
remains of a large artificial salt lick 
still exist. National Park Service of- 
ficials stopped providing salt for goats 
several years ago when they noticed 
that excessive trampling in the area 
of the lick was resulting in habitat 
destruction. The area is now almost 
completely devoid of vegetation, but 
the animals still use the lick exten- 
sively, apparently seeking minerals 
that have percolated into the soil. 
(Hikers sometimes unwittingly in- 
crease such deterioration by pausing 
to relieve themselves by the trail. Hu- 
man urine has a salty taste and is 
very attractive to mineral-starved 
goats. The trampling, digging, and 
licking by animals at these sites can 
be a factor contributing to erosion.) 
Mountain goat summer range must 
also provide a variety of microhabitats 
that aid the animals in thermoregu- 
lation. During the course of a year, 
mountain goats are subjected to ex- 
tremes of both hot and cold, and their 
body temperature is regulated through 
physiological and behavioral means. 
The goats’ long, dense fur, which helps 
to reduce heat loss during the winter, 
is shed during the summer when tem- 
peratures may soar over 90° F. Rum- 
inants are particularly susceptible to 
overheating since their digestive sys- 
tem has a built-in “furnace.” The colo- 
nies of microorganisms, which break 
down cellulose, generate heat as a re- 
sult of their own metabolic processes. 
This heat, combined with a goat’s own 
heat and with solar radiation absorbed 
from the environment, can result in 
thermal stress if there is no compen- 
sating movement into a cooler micro- 
habitat. On a hot day, the animals 
typically seek shade or recline on 
patches of snow. When overheated or 
harassed by insects, a goat may also 
lie in dirt and, with a quick movement 
of a foreleg, throw cool soil over its 
body. This behavior is a further cause 
of erosion, resulting in the creation 
of wallows, large patches of exposed 
soil used regularly for dust bathing. 
Once the soil surface has been dis- 
turbed in this manner, erosion is ini- 
tiated and can be expected to continue 
even in the absence of goat use. 
The white coat of the mountain goat 
may also function in thermoregula- 
tion. The white color might be a form 
of protective coloration and, in fact, 
predators may find the goats more 
difficult to see when the mountains 
are hidden by a veil of snow. Such 
an advantage does not extend into the 
summer, however, when snowfields 
melt and alpine meadows fill with lush 
green vegetation. The traditional view 
is that in this season the white coat 
may act to reflect solar radiation and 
so keep the goats cool; but recent phys- 
iological studies have also shown that 
in a windy environment, such as the 
mountains in winter, more heat is ab- 
sorbed by a light coat than by a dark 
one. 
Many areas of the Olympic Moun- 
tains possess the essential components 
of the mountain goat’s habitat. The 
distribution of such favorable ecologi- 
cal characteristics has influenced the 
population growth of these introduced 
herbivores and their pattern of dis- 
tribution. Parkwide surveys have con- 
firmed that the animals now inhabit 
nearly all of the region’s suitable habi- 
tat, and birth and dispersal rates sug- 
gest that the population is still ex- 
panding. 
Since 1977, 20 percent of the ani- 
mals tagged in the high-density study 
65 
