Volume XXI - 1955
Water Bears In Crater Lake
By C. Warren Fairbanks, Assistant Park Naturalist
One day in early August, 1954, Ranger Naturalist John Rowley and I
were prowling about the base of Wizard Island, situated near the west
end of Crater Lake. This was an important hunting expedition. Extensive
and careful preparations had been made before starting the trip. First,
adequate provisions had been secured by making arrangements, well in
advance, with the dining hall for a supply of sandwiches and various
suitable accessory food items -- it was to be an all day trip.
After checking the supplies, we stowed them carefully, along with
other gear, into pack sacks. These in turn were loaded into a conveyance
that carried us to the Rim Village, which was as far as we could travel
by motor vehicle. The remainder of the way to Crater Lake had to be
negotiated on foot. Upon unloading at the Rim, therefore, we shouldered
our packs and headed down the Lake Trail -- a trek of 1.6 miles.
On this particular day we took our time. In addition to being rather
heavily loaded with essentials, we had brought along various pieces of
photographic equipment in order to make a complete pictorial record of
our operations. Consequently, we stopped now and then to capture with
lens and film interesting features and events along the way.
At the bottom (of the trail, not the lake), we obtained a boat with
outboard motor -- previously arranged for, to be sure. As quickly as
possible, yet without undue haste, we loaded our gear into the boat for
the one and one-half mile voyage to Wizard Island -- the water being a
little too cool for comfortable swimming, especially with full field
pack -- and took off, after the motor finally started, of course.
Upon reaching the island, we picked up other equipment which had
been cached there during a preliminary exploratory mission and, now
completely outfitted, set course for the shore of Fumarole Bay, chief
base of operations.
Fully half a day had been consumed in this phase of our venture, so,
reaching our destination, we sat down to devour our repast. All the
while, excitement of anticipation for the hunt kept mounting within us.
It was even difficult to make ourselves take the time to properly
dispose of paper sacks and milk cartons for return to a suitable trash
repository before heading out. In fact, John Rowley, younger and more
impetuous, and having seen some sign which suggested the presence of
game, set off along shore while still munching a sandwich. This he held
firmly in his left hand while using his right to aid his progress along
the rough and steep terrain.
I was not long in following, however. Presently, initial excitement
having been replaced by the steadier verve of actual search for the prey
we were working the area methodically as a well-accustomed team, leaving
no stone unturned in the effort to exhaust all possibilities for finding
their lairs. Then, having examined the original site thoroughly, we
returned to the boat to seek other likely spore.
Finally, and much later, each of us sighted and drew fine bead --
first I, then Mr. Rowley -- on fair game. There, caught squarely in the
centers of the fields of our respective hundred-power scopes, were two
water bears -- the first ever reported to be seen in Crater Lake. Mine
was so nearly hidden by lush green vegetation that I could just barely
(no pun intended) make out his -- or, more probably, her -- outline.
Ranger Naturalist Rowley's, on the other hand, was lumbering along
nearly always in the open. No triggers were pulled, however -- park
regulations do not permit action.
We had, of course, returned to the laboratory, and our " scopes"
were microscopes. Water bears are very small animals. Although the
largest of them are a little over one twenty-fifth of an inch in length,
most tardigrades, as they are known to students of zoology, are only
about half that size or less (Pennak, 1953). Actually, they are not very
well known, even to the zoologist. The name of this animal means "slow
walker," and the clumsy lumbering way in which he gets around is very
suggestive of his common name -- water bear.
Since he has four pairs of short stumpy legs, some people consider
him to be a rather distant cousin of the spider, while others place him
in a completely separate division of the animal kingdom. Be his
relationships as they may, these two specimens proved to be a very
interesting find. To our inexperienced eyes, they appeared to belong to
the genus Macrobiotus, although this has not been definitely
determined. The one which came under my microscope was taken from the
bottom of Fumarole Bay. It was collected with a mass of filamentous
green algae (simple green plants) that was lifted with a plant grapple
(Fairbanks and Rowley, 1954) from a depth of twelve feet. The other
specimen, oddly enough, came from rotting wood lying in water along the
nearby shore of the island.
Even though water bears are little known, they are reportedly very
abundant in various aquatic and semiaquatic habitats (Pennak, 1953).
Frequently they are found on masses which are intermittently wetted by
rain or splashings from streams. The animals have the ability to shrink
up and become inactive when conditions such as insufficient moisture
make active existence impossible. In this way they are able to remain
alive in a state of minimum activity, which can persist as long as there
are food reserves available within their bodies.
Tardigrades feed mostly upon plant cells, from which they extract
the fluid contents by a sucking action. They also may be cannibalistic
to a certain extent. In the main, however, they should be classed as
converters which make the food substances manufactured by plants
available to other animals. They, in turn, are preyed upon chiefly by
certain protozoans and by roundworms (Pennak, 1953). Therefore, they
form one link in the food chain which always begins with the green plant
and which leads ultimately to some large animal.
It might be correctly inferred that the "hunting expedition"
mentioned above was not organized to track down the water bear. To be
exact, we, were searching for other forms of life. The find, however,
was one of considerable interest because it brought to light a
little-known animal which had not previously been reported as part of
the fauna of Crater Lake National Park.
Literature Cited
Fairbanks, C. Warren, and John R. Rowley. 1954. Tribute to the
clarity of Crater Lake. Nature Notes from Crater Lake
20:34-36.
Pennak, Robert W. 1953. Fresh-water Invertebrates of the United
States. New York, The Ronald Press. ix, 769
The Harvest Of A Quiet Eye
By Clarence J. Nordstrom, Ranger Naturalist
One afternoon in mid-July, when sunbathing in an open space not far
from Park Headquarters, I heard the sudden whir of a miniature airplane
motor within inches of me. It passed as quickly as it came. In a matter
of seconds the sound was repeated. Watching for the cause, I shortly saw
a blurr as something shot toward me and then quickly disappeared,
accompanied by the same hum. It suddenly dawned on me that this was the
season of the hummingbirds and that they, like humans, are curious
creatures and may have been shooting low merely to view better an object
obviously out of place in their habitat.
* * * * * * * * * *
It was afternoon in late July, after a body-shaking ride over one of
the fire roads. I had gone to the Crater Spring bogs for the purpose of
getting photographs of three insect-eating plants, including two
sundews, Drosera rotundifolia L. and Drosera angIica
Huds., and the rather rare bladderwort, Utricularia intermedia
Hayne.
While examining a sundew, my eyes happened to fall upon a most
fascinating sight. On a nearby flower, a lady's thumb, a bee had settled
in its search for nectar. Upon this insect, with legs wrapped around it,
was a large and beautiful, white, spotted spider having a head tiny in
comparison with its extremely large, round body. Close examination
showed that the bee was shrunken and motionless. It was evident that the
spider had either paralyzed the bee or stung it to death. Then it had
proceeded to suck out the body juices, filling its own body seemingly to
the bursting point -- a habit characteristic of the crab spiders
(thomisids), to which group this individual apparently belongs.
The bee was in perfect condition except for this aspect which suggested
a deflated balloon.
Cony beside a red elderberry bush.
From Kodachrome by Welles and Welles.
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* * * * * * * * * *
When I was casually winding my way down the Lake Trail one morning,
with eye ever alert for a new flower just emerging, a strange bird, or
some other thing of interest, my attention was caught by a green branch,
approximately sixteen inches long, moving crosswise over the trail. It
appeared to be propelling itself, until -- after a few seconds, at the
head end -- a cony suddenly appeared from nowhere. The long green leaves
parted, exposing the little brown creature which evidently had decided
that early August was not too soon to begin preparing its hay pile for
the long winter ahead.
Apparently the animal's attention was so intent upon its
instinct-inspired task that it either failed to notice or deliberately
ignored movement that ordinarily would have driven it to cover. Since
the moving branch was within three or four feet of me before it
disappeared under the rocks, I could clearly distinguish the red
elderberry leaves that the cony had chosen to include in his winter food
supply.
* * * * * * * * * *
Sitting on a ledge within a few feet of the Lake Trail during a
prolonged pause on my upward climb, I noticed nine stationary white dots
on the blue water. They formed a perfect arrow, four making up the head,
five the shaft.
Suddenly the arrow broke as the dots changed position and as some of
them left the surface and winged their way aloft. Probably never again
will I see nine California gulls, Larus californicus Lawrence,
line themselves up, by pure chance, in this perfect formation.
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