Many animals do not possess an adequate mechanism for maintenance of
constant body heat. Some of these, taking advantage of the slowness with
which water changes temperature, live mostly in an aquatic environment.
Few can endure the cold winters of high altitudes.
Unlike other animals in National Parks, fish may be taken, under
regulations designed to conserve the resource. As long as you have a
State fishing license, you may exercise this privilege in Rocky Mountain
National Park. The season and catch limits vary from year to year; you
are urged to ask a park ranger about current regulations.
[Illustration: Coyote.]
The original trout in the park is the BLACK-SPOTTED, or CUTTHROAT,
TROUT. Once found only in the northern Rockies, it has been transplanted
widely. It has numerous subspecies and color variations, but here it is
usually an olive-green on back and upper sides, shading into a yellowish
cast on lower sides. The lower surface becomes red at spawning time. The
body and fins are black-spotted. The red streak on each side of the
lower jaw has given it the name "cutthroat." Its principal foods are
insects and small aquatic animals. Spawning takes place in midsummer in
the high country.
The BROOK TROUT, originally native east of the Mississippi, was
introduced into this park, where it has thrived and maintains itself
through natural reproduction in many lakes and streams. It is
olive-green to gray, with a sprinkling of red and gray spots on the
sides. The front borders of the lower fins and the lower borders of the
tail are white. Its food includes insects, worms, small minnows, and
crustaceans. It spawns in autumn; the female deposits the eggs in a
depression she scoops out in the streambed. After the eggs are
fertilized, she covers them with gravel and leaves them to hatch
unattended.
The RAINBOW TROUT is another nonnative trout of the park waters. Its
original range was on the Pacific slope of the Sierras and the Cascades,
but it has been transplanted widely. It is bluish-olive above the
lateral line, changing to silvery-green on the sides. Its name is
derived from a broad, reddish stripe on the sides. It eats insects,
worms, and smaller fishes, and is a favorite of the angler for its
fighting ability and tendency to break water when hooked. Spawning
occurs from autumn to spring, depending on the altitude.
[Illustration: Cutthroat trout.]
The most common amphibian in the park is the bright-green to tan LEOPARD
FROG. Restricted to damp areas near ponds or creeks, it is most likely
to be seen in spring and early summer when the gelatinous egg masses are
being laid. The tadpoles develop into mature frogs in about 3 years.
Until then, it lives on plant food; after maturity, it eats insects and
worms. It is found in Moraine Park, Horseshoe Park, and other moist
grassland valleys.
The THREE-LINED TREEFROG, our smallest amphibian--about an inch long--is
often mistaken for a young leopard frog. Although it is a treefrog,
possessing disks on its toes, it is seldom seen in trees; it prefers
small ponds or swampy grassland. It is sometimes found under rockpiles
or pieces of damp wood. Despite its small size, its loud chirps in
spring and summer can be heard a half mile away. During its singing, a
vocal sac beneath the lower jaw inflates to a size larger than the
creatures head. It is easily recognized by the three stripes down its
back. Look for this diminutive amphibian at Gem Lake.
The insectivorous MOUNTAIN TOAD, a nondescript denizen of marshy lake
habitats, is common in Cub Lake Valley, Hallowell Park, and in the Ouzel
Lake area in Wild Basin. In late spring, large numbers congregate in
ponds to lay strings of eggs. The small tadpoles become adults by the
end of summer.
[Illustration: View of Mount Ypsilon from near Bear Meadows approach
to Trail Ridge Road.]
The TIGER SALAMANDER is one of the oddest animals of the park.
Salamanders do not walk out of fires, as medieval tradition had it, but
are amphibians. Unlike frogs and toads however, they retain their tails
after reaching maturity. They hatch from eggs in shallow ponds, breathe
by means of feathery external gills at the back of the head. Later, the
gills are absorbed and the salamander begins breathing with lungs; it
then leaves the water for a moist underground burrow, returning to ponds
in early spring to lay eggs on plants or debris in the water near the
shore. In southern latitudes, the larvae (gill-breathing forms) are able
to lay eggs; these are the _axolotls_ of Mexico. Our local variety of
the tiger salamander is about 8 inches long, gray-brown with dark spots.
It is found in Sheep Lake, around which large numbers occur during the
spawning season in June, and is often seen in suitable habitats along
Cub Lake Trail. It eats insects, insect larvae, worms, and small snails.
It is harmless to humans.
The only reptile in the park is the MOUNTAIN GARTER SNAKE, which is
found throughout the mountainous areas of Colorado. Because of its
fondness for water, it is often erroneously called a "water snake." It
is greenish-gray and may reach a length of over 2 feet. It feeds on
frogs and worms; it is entirely harmless to man, but is capable of
giving off an offensive odor when handled. The young are born alive in
midsummer. These snakes may be seen near most of the marshy ponds or
slow-moving streams in the park. The ponds in Cub Lake Valley and in
Hallowell Park are favorite haunts of these interesting creatures.
No rattlesnakes or other poisonous reptiles have ever been found in the
park. Reports of rattlesnakes near Glen Haven mark the highest known
occurrences in this region--a fact that, while contributing to the
visitor's peace of mind, puzzles many people. This absence, or relative
scarcity, of cold-blooded animals is probably due to the climate--long,
cold winters and chilly summer evenings. The lower amount of oxygen at
high altitudes may also be a factor. On the tundra, many pools are free
of ice for only about 6 weeks--scarcely time for frogs' eggs to hatch
and for larvae to develop lungs before freeze-up. The cold nights, even
in midsummer, would inhibit a large snake's movements to such a degree
that it would probably starve. Thus you can hike in the park in
confidence that you will encounter no poisonous snakes.
[Illustration: Fishing is a popular recreation made doubly
attractive by the mountain setting of the park waters.]