DESERT TRAIL MAP CALIFORNIA
The Desert Trail is another new long-distance trail which is in the early stages of being built. Some day it should extend all the way from Mexico to Canada, crossing the High Desert of California, Nevada, Oregon, Idaho, and Montana.
Sections totaling about 250 miles have been finished in Oregon, Nevada, and California. Only a small portion of the California route, in the southernmost region of the state, has been completed so far.
For Further Information: Desert Trail Association, P.O. Box 537, Burns, OR 97720. A trail guide for the California section is available from this organization.
DESERT TRAIL MAP CALIFORNIA Photo Gallery
All four limbs have five fingers and no thumb but they cannot be opened separately, as we open our fingers, because they close together and have to be used as one to open, close or hold. The forelimbs can also be used for gripping objects or prey, but the hindlimbs cannot grip or hold. There is webbing between the fingers which turns them into very efficient fin-like flippers for swimming. On the surface, the heartbeat of the seal can be as high as 120 beats per minute but when they submerge, this drops to fewer than ten beats and sometimes the heartbeat is no more than just a flutter, which gives the seal its remarkable ability to stay underwater over such long periods. Just prior to the point of diving, it will breathe in and out several times and then exhale, leaving the lungs almost empty of oxygen while it is below the surface. The nostrils close completely, and muscles prevent them from being forced open by the pressure of water. As there is little or no oxygen in the lungs to be passed by circulating blood, the heartbeat rate is low, but it is enough to keep blood flowing to the brain, a sphincter muscle near the heart reducing the blood flow to the kidneys, intestines and extremities of the body, starving these of blood, while the vital organs, heart, lungs and brain still receive blood and oxygen. There are airlocks in the lungs too, which are intended to stop any air getting into the respiratory cells and in turn preventing nitrogen being absorbed under pressure into the blood. If this did happen as the seal rose to the surface, bubbles of gas would form in the small blood vessels as pressure reduced and cause the bends, which would prove fatal for the seal as it would for a man. With the circulation slowed down in this way, the seal’s body temperature falls, especially in the flippers and extremities, so that when it comes to the surface it shivers for a short while, but after a couple of deep breaths, it very quickly returns to normal without coming to any harm.