Nature Notes

Vol. XII February - 1934 No. 2

Amphibians of Mount Rainier National Park

The amphibians, including frogs, toads and salamanders, form an interesting but little known and appreciated section of animal life in Mount Rainier National Park. Throughout the world, there are some 2000 species of amphibians and of this number Mt. Rainier National Park is represented by twelve. Seven of this group are salamanders, newts, "waterdogs" etc.--the tailed amphibians; while five species of frogs and toads--the tailess amphibians--complete the group.

Of this small unit of twelve species some representatives may be found living and breeding from the lowest elevations along the boundaries of the park to as high as 6000 feet above sea level. The marshes of the lower Canadian Zone resound with a multitude of frog voices during the breeding season in early May and later at the higher elevations, hardly before the snow has disappeared from around the small lakes and ponds in the Hufsonian Zone, we may find the jelly-like masses of eggs of various frogs and salamanders that breed at that elevation.

Most amphibians lay their eggs in water of small pools, lakes or in streams, though some find moist places on the ground more suited to their needs. Species of two genera follow the latter procedure in Mt. Rainier National Park, those being the Washington Salamander (Plethodon vandykei), the Western Red-backed Salamander (Plethodon intermedius) and the Red or Oregon Salamander (Ensatina eschcholtzii). The eggs of all other local amphibians are laid in water. The number of eggs vary with the species and individual, ranging from less than twelve to more than one hundred. The egg consists of a yolk--the dark center--and swells to a large size to form a protective covering for the yolk. The form in which the eggs of many amphibians is laid also differs. In the case of the Tree Toad, Western Red-backed Salamander, Washington Salamander, Pacific Coast Newt and Pacific Giant Salamander, the eggs are laid in small clusters. Those of the Northwest and Long-toed Salamander as well as the Western Spotted Frog and Wood Frog are laid in large masses while the Northwest Toad lays its eggs in long strings. After the eggs hatch, the tadpoles pass through various stages of development with which everyone is familiar and which is illustrated for frogs on the opposite page, finally (if the individual is very lucky) developing into a mature adult amphibian.

To many people, the amphibians seem so near like some reptiles that the animals in these groups are so times confused. Because of this confusion, many often regard these two groups in the animal kingdom as one. However, this is far from being the case. There is as much structural difference between reptiles and amphibians as there is between birds and mammals even though the former do not possess outward characters of a truly distinctive kind (such as the feathers of a bird or the hair or mammary glands of a mammal) by which anyone quickly identifies these latter groups one from another. A few of the most obvious distinctions are as follows:

Amphibians Reptiles
1. Lay eggs in water or in moist places on land. 1. Never lay eggs in water.
2. Have metamorphosis--going thru several changes from egg to air breathing aduly. 2. Young hatched or born with the form of parent.
3. Skin slimy and not possessed of scales 3. Skin scaly.
4. Larvae breath by means of gills for a time. 4. No larval stage and hence no gills present.

In addition to the confusion of amphibians with the reptiles, the public has associated many peculiar superstitions with the amphibians and this is particularly true of the toads for many people still believe that toads, if handled, will cause warts. Nevertheless, contrary to this belief, this is not the case. They do possess glands which secrete a slimy acrid fluid which causes many of their enemies to leave them alone. If a toad is eaten this fluid acts in a very distasteful and disagreeable manner upon the membranes of the throat and mouth. After one experience, the animal who secured such a meal will probably not desire another of like character very soon. The "warts" found on toads contain the glands for the secretion of this fluid. All amphibians have such glands in some form or other, though they are more pronounced in the case of the toad. (C.F.B.)

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