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Reptiles and Amphibians of Yosemite National Park

Handbook of Yosemite National Park (1921)
by Joseph Grinnell and Tracy Irwin Storer

Next: Fishes of YosemiteContentsPrevious: Mammals of Yosemite

Reptiles and Amphibians of Yosemite National Park


By Joseph Grinnell, Director, and Tracy Irwin
Field Naturalist, Museum of Vertebrate
Zoölogy, University of California

(Contribution of the Museum of Vertebrate Zoölogy of the
University of California)

Next lower in the evolutionary scale below the birds and mammals stand the reptiles, including the turtles, lizards, and snakes, and next below them the group known as amphibians or batrachians comprising the salamanders, toads and frogs. The Yosemite region contains twenty-one species in the first named group and eleven in the second. Among all these "cold-blooded" vertebrates there is but one poisonous species, the Pacific Rattlesnake; none of the others need be feared at all. All the snakes, even the Rattler, will slip away quietly unless cornered and provoked into fighting. As normal parts of the protected animal life in Yosemite National Park no person should kill any of these reptiles or amphibians, save the Rattlesnake.

As a rule, the numbers of both species and individuals decrease with altitude. Above the Transition Zone there are but few reptiles, though amphibians are well represented as to individuals. One species in the latter group, the Pacific Tree-toad (Hyla regilla), may be heard in spring at almost all altitudes. Although scarcely an inch in length, it is notably hardy and ranges up even to timberline. In the high mountain meadows will be found a toad peculiar to the region, the Yosemite Toad (Bufo canorus), and its mellow notes are pleasing additions to the chorus of bird songs just after the snow leaves. Yellow-legged Frogs throng all the stream sides and lake margins up to timberline. The salamanders are less in evidence, and careful search is required to locate them. One species, the Lyell Salamander, is known only from the Yosemite Park, the two known specimens having been taken in the head of Lyell Canyon at an altitude of 10,800 feet.

The Pacific Mud Turtle is the only representative of its tribe found in the region; it has not yet been discovered higher than the 3000-foot level in the western foothills. Of the nine kinds of lizards the most common and most widely distributed group comprises the "Swifts" (Sceloporus) which live about trees and on rocks and logs. These are dark bodied, with more or less blue on the under surface. The Alligator Lizards (Gerrhonotus) which have long slender bodies, small legs and large diamond-shaped heads are found in grass and under brush piles and chaparral. These are reputed to be poisonous, but their only defense when handled is to give their captor a sharp pinch in their relatively heavy jaws. They have no poison glands. In the leafy débris beneath the golden oaks along the walls of Yosemite Valley there is the large Red-headed Skink (Plestiodon skiltonianum) which has a pinkish-red head and olive-green body. It has exceedingly smooth scales so that it can slip through one’s fingers as if oiled.

The snakes of the region comprise eleven species. In the Yosemite Valley is found the Rubber Snake (Charina bottae), a smooth scaled "double-ended" relative of the pythons and boas of the tropics but not known to exceed thirty inches in length. There are numerous Garter Snakes (Thamnophis) in the region. These are often called Water Snakes, in recognition of their preference for moist meadows and the margins of pools. They may usually be identified at once by the three light yellow stripes along the body, one on each side and the third along the middle of the back.

The most beautiful of the local snakes is the Coral King Snake, a small, smooth scaled, perfectly harmless species which lives along the golden-oak . talus slopes and is frequently met with on the lower trails. Its banded coloration is of black, red, and yellow, all of bright tone. Gopher Snakes have been found in the western foothill country but have not yet been recorded within the park itself.

The Pacific Rattlesnake is likely to be found anywhere in the Yosemite National Park below about 8500 feet altitude, but in Yosemite Valley, and along the well-traveled trails so many of the snakes have been killed that the species is becoming rare in most of these places. The Rattler has many distinctive features, and in consequence will be recognized at once, even by persons who know it only by reputation. The head is bluntly triangular, the neck constricted; the stout body is covered with ridged or keeled scales, and the short tail has at the end a short segmented rattle which the animal can vibrate to produce the well-known warning sound. The Rattlesnake is essentially a ground dweller and seeks refuge at night and during the winter in a crevice in the rocks or a hole in the ground. Occasionally a number collect together in a favourable location, forming one of the rattlesnake "dens" really more common in folklore than fact. The rattlers subsist largely upon small rodents—ground squirrels, chipmunks, meadow mice, and pocket gophers.

From time to time the Rattlesnake, like other snakes, sheds the outer layer of the skin, and each time this occurs a new segment is added to the rattle at the end of the tail; for the substance of the rattle grows in continuation with this outer "epidermis." These molts do not occur at any regular time, and some individuals probably molt much oftener than others so that the number of rattles cannot be taken as an index of the age of the snake, only of the number of molts it has undergone. The "button" at the end of the rattle and several of the terminal segments are sometimes lost through accident and so a very large snake may have only a few rattles. The largest number known to us to have been found in one series was twenty-two; eight to ten is near the average. At the time of molt the skin covering the eye is cast off and just previous to this operation the eye may be slightly clouded over. This has given rise to a belief that Rattlesnakes become "blind" (especially in late summer when many individuals molt), and it is currently believed that the snakes are then more likely to strike without rattling than at other times of the year.

When excited the Rattlesnake vibrates the tip of the tail rapidly, causing the horny rattle to give forth a cicada-like, buzz that is unmistakable. If danger threatens, the snake places its body in a series of S-shaped curves, the tip of the tail being held vertically. To "strike," the reptile straightens out suddenly, lunging at its prey or enemy, dropping the lower jaw and erecting the hollow teeth or "fangs" in the roof of the mouth so that they point almost straight forward. At best the Rattler cannot strike more than two-thirds its total length. Stories of snakes "jumping" at their enemies are without foundation. If the snake hits the object of its attack the two hollow fangs are buried in the flesh, the lower jaw is brought up and poison is forced into the wounds. Leather tramping boots or puttees usually afford full protection against the Rattlesnake, as the animals are not known to strike much if any over twelve inches above ground.

If a person chances to be struck by a Rattler certain things should be done, promptly but with as little flurry as possible.

(1) If bitten on the leg or arm, apply a tourniquet above the wound, that is, toward the heart from the bite. This is done in order to stop the flow of blood toward the heart. A bandana handkerchief twisted tight by means of a stick makes a good tourniquet.

(2) Cut the wound open with a pocket-knife, or cauterize with a red hot iron. If possible, inject a solution of potassium permanganate into the surface immediately surrounding the bite. If the solution cannot be made, apply crystals of permanganate directly at the place of the bite.

(3) After about one hour loosen the tourniquet slightly for a fraction of a minute, then tighten down again; after this, loosening and tightening should be done every fifteen minutes or so.

(4) The patient should be placed in a comfortable position. A mild stimulant, such as coffee, may be given. Do not give whiskey. A doctor should be summoned as soon as possible.

[Editor’s note: the above information for snakebite first aid is obsolete and should not be followed. In particular, do not use a tourniquet, do not cut the wound open, do not apply heat, and do not apply ice.—DEA]


Dickerson, M. C., 1906. The Frog Book. (New York, Doubleday Page & Co.) xvii+253 pp., 16 col. pls., 96 half tones, 36 figs. in text.

Ditmars, R. L., 1907. The Reptile Book. (New York, Doubleday Page & Co.) xxxii+472 pp., 136 pls.

Grinnell, J., and Camp, C. L., 1917. A Distributional list of the Amphibians and Reptiles of California. University of California Publications in Zoölogy, vol. 17, pp. 127-208, 14 figs. in text.

Van Denburgh, J., 1897. The Reptiles of the Pacific Coast and Great Basin. California Academy of Sciences, Occasional Papers, No. 5, 236 pp., many text figs.

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