• Mount Rushmore, Washington, Jefferson, T. Roosevelt, Lincoln framed by ponderosa pine trees under a bright blue sky.

    Mount Rushmore

    National Memorial South Dakota

Amphibians

Amphibians, like the three frogs found at Mt Rushmore, go through many changes on their way to becoming adults. Once the eggs are attached to submerged grass or twigs they will hatch in a few days. Tadpoles, newly hatched frogs, grow rapidly and feed on algae that grow on submerged objects. By June most tadpoles have legs and have the appearance of small froglets. Froglets that survive will hibernate until spring when the warmer temperatures bring them out again.

Striped Chorus Frog
The Striped Chorus frog is a small frog only measuring about 1 ½ inches. They can be found in a variety of habitats including marshes, meadows, and other open areas, and are most active at night or in moist weather. Breeding season begins in mid-March and continues through late May. Females lay 500-1500 eggs that attach to submerged grasses or sticks, with hatching occurs in 3-14 days. Striped chorus frogs eat a variety of small invertebrates including ants, flies, beetles, moths, caterpillars, and spiders. These frogs are important ecologically because they help control insect population where they live, but they also act as a critical indicator species.

Western Chorus Frog
The Western Chorus frog is another small frog measuring only ¾-1 ½ inches. Their habitat is often in or near areas of shallow, often temporary, bodies of water, but also can be found in grassy areas, woodlands, and swamps. Breeding season begins in mid-March and runs through late May. The female lays 500-1500 eggs and hatching occurs in 3-14 days. Western Chorus frogs eat ants, moths, caterpillars, and other small invertebrates. This frog also acts as a critical indicator species. It is valuable in determining the overall health of the aquatic and terrestrial ecosystems. Due to its thin skin it is very susceptible to contaminants and can indicate high levels of pollution in areas where changes in ecology or morphology occur.

Northern Leopard Frog
The Northern Leopard Frog is a medium sized frog that ranges in length from 2-5 inches. They are found in a variety of habitats including lakes, streams, ponds, and marshes. These frogs are common in backyards in the summer. Breeding season begins in the spring when the air temperatures are above 68 F in mid-March or early April. Females will release 3000-6000 eggs which attach to twigs or plants and will hatch in about two weeks. Northern Leopard Frogs will eat grasshoppers, crickets, beetles, non-aquatic insects, and other frogs. The Leopard Frog is experiencing a drop in numbers due to a variety of factors, including harvesting for bait, increased pesticide use, and loss of habitat.

Frogs are unique creatures; they have a combination of physical and biological characteristics that make them sensitive to changes in the environment such as pollution and loss of habitat. Frogs also have venom glands that act as protection against predators secreting irritants or toxins that may cause a predator to drop the frog from its mouth if it is picked up or bitten. The unpleasant experience may deter that predator from bothering that type of frog again. Since frogs prefer areas that are moist, it may be difficult to see one on your visit, but if you listen closely at night in the late spring you just might hear the call of a male frog.

Did You Know?

Did You Know?

Geologists estimate that the granite at Mount Rushmore National Memorial will erode only 1 inch every 10,000 years.