Leopard frogs, northern leopard frog, southern leopard frog
Adult leopard frogs measure 2-5 inches (5-13 cm) in length. Tadpoles can grow to 3 inches (8 cm) or more before growing arms and completing metamorphosis. When leopard frog tadpoles complete metamorphosis the juvenile frogs often only measure an inch or so in length. The process of going from egg to tadpole to frog takes between 3 and 6 months to complete. In cool or overcrowded conditions, or in captive situations where the tadpole does not have ample food, it can take much longer to turn into a frog. Juvenile frogs take 1-2 years to mature.
Leopard frogs have an emblematic frog-look, with powerful hind legs, a streamlined body, and slightly angular head. There are more than a dozen species of leopard frog but they all have black spots on their dorsal side, hence the common name leopard frog. The background color behind the black spots ranges from a bright grass green to a dull tan or brown depending on species. The ventral side is white in color and lacks pattern.
Distribution, Habitat and Behavior
Leopard frogs are found throughout North America. The distribution of the northern leopard frog (Lithobates pipiens) and southern leopard frog (L. sphenocephals) covers most of the continent. The southern leopard frog is found in the southeast United States and the northern much of the rest of the U.S. and Canada. Other species of leopard frogs have much smaller distributions. Some, such as the Ramsey Canyon leopard frog (L. subaquavocalis), are confined to only a handful of ponds.
Adult leopard frogs are found near water. They often live near the water’s edge in grassy habitat. Here leopard frogs may spend the day on land, jumping into water for safety if disturbed. They are skittish and jumpy frogs, both in nature and captivity.
Leopard frogs are one of the most familiar frogs in the United States. Most often northern leopard frogs and southern leopard frogs are kept in captivity. Other species are maintained by zoos and aquariums for conservation breeding purposes.
Although occasionally adult leopard frogs are offered for sale at pet stores, more often their tadpoles are sold. Leopard frog tadpoles are rarely labeled as such but instead may just be sold as “tadpole” without regard for what species it could be. Other species like green frogs (Lithobates clamitans) are also regularly sold this way.
Caring for Tadpoles
Leopard frog tadpoles are not difficult to maintain and they can be kept similar to fish. The most important part of their care is water quality. Use a large volume of water (upwards of 10 gallons) if possible because the larger the volume of water the more stable the conditions. A power filter will help maintain water quality in addition to frequent partial water changes. Removing a third of the water once every 1-2 weeks is good practice. If tap water is used, an aquarium water conditioner that removes chlorine and chloramines should be used to treat the water a day in advance of the water change.
Inside the aquarium very little is needed. In fact, tadpoles can be kept on a bare-bottom, although providing gravel will allow increase surface area for helpful bacteria to grow which help maintain water quality. Floating vegetation can be grown in the aquarium if strong lighting is used. Floating plants provide cover and help maintain water quality.
Leopard frog tadpoles will eat standard aquarium fish foods. There are also diets designed specifically for aquatic amphibians and tadpoles. Tadpoles will also feed on aquatic plants and detritus within the aquarium. Feed daily and use a variety of foods if possible, but make sure not to overfeed. All food should be eaten by the tadpole within an hour or less. If there is excess food in the aquarium it should be removed.
When front arms are about to pop through make sure there is easy access to land. You can do this by decreasing the water depth and adding a large rock or aquarium decoration that breaks the water’s surface. Another option is to float a piece of cork bark in the water. At this point the tail will begin to be absorbed and the tadpole will not require food. Once the tail is fully absorbed the little frog will need frequent feedings of live insects as described below.
Leopard Frog Housing
Adult leopard frogs require a large amount of room to comfortably live in captivity. A 30 gallon aquarium that measures 36 inches long by 12 inches wide by 16 inches high (91 cm by 30 cm by 40 cm) is large enough for one or two adult frogs. Young frogs can be kept in smaller enclosures. A secure screen cover is essential to prevent escapes. Large plastic bins or stock tanks often make better housing than typical glass aquariums because of their non-transparent sides. Leopard frogs are prone to attempting to leap through glass or transparent materials and may injure themselves in the process.
Leopard frogs are semi-aquatic and should be provided with both a land area and large water area. There are many ways to create semi-aquatic environments for captive amphibians. For leopard frogs, often the easiest is to fill an aquarium a third of the way full with water and then place several large rocks towards one end that protrude from the surface of the water. Use plants or pieces of driftwood on top of the large stones to provide cover and help frogs feel secure. Also, importantly, make sure the rocks are stable and will not fall over or harm the frogs.
Another way to create a semi-aquatic habitat for leopard frogs is to create a small shoreline setup. In this method, medium to large grade gravel can be used. Push most of it to one side to form a land area, leaving the other half of the aquarium with a thin layer. The slope between the two sides should be gradual. It may helpful to place pieces of slate or river rocks alongside the slope to help hold its form.
Once the rocks are in position, the aquarium can be filled with enough water so that the water line is slightly below the land area. All exposed gravel on the land section should be covered with large river rocks, sheet moss, soil, or a combination to prevent the gravel from being ingested by leopard frogs during feedings. Live or fake plants can be used in both the water and land area as shelter along with driftwood, cork bark, and rocks.
In semi-aquatic setups it is often helpful to use a small submersible power filter. In large setups a canister filter can be used instead. The output of all filters should be deflected with a rock to prevent a large current from being formed. Leopard frogs usually live near still or slow-moving water and do not need much of a current in their enclosure.
Perform water changes weekly, with around half of the water being removed at a time. It may be helpful to use an aquarium vacuum to suck out the waste that gets caught in the gravel on the water side.
There are many other ways to make semi-aquatic setups but some of them are not suitable for keeping leopard frogs in. Make sure that if small gravel is used on the land area that it is covered with large rocks, sheet moss, or soil so that it cannot be swallowed by the frogs. If a large float is created using cork bark or plastic make sure that the frogs cannot get stuck beneath it and drown.
It is important to put a terrarium or aquarium background on the sides and the back of the cage to prevent the frog from trying to jump through the glass. If tap water is used in the tank it should be treated with tap water conditioner to remove chlorine, chloramines, and heavy metals. Certain types of bottled spring water can be used instead of treated tap water.
Temperature and Lighting
Leopard frogs live well when kept between 60°F and 80°F (16°C and 27°C) for most of the year. Submersible aquarium heaters can be used to heat the water, if needed, and a low wattage incandescent light bulb can be positioned over the land side to create a warm area on land. Take care that the light does not overheat the enclosure. Use a good quality thermometer to measure the temperature in different parts of the cage and monitor it carefully during different times of the year to make sure it stays within a safe range.
Like most frogs, leopard frogs eat live insects and other invertebrates in captivity. Most of their diet can be composed of crickets and earthworms. Other food items including wax worms, small or cut-up night crawlers, silkworms, and roaches can be offered in addition to crickets and earthworms. Some leopard frogs will also eat or attempt to eat aquatic animals like ghost shrimp and feeder guppies. Feed anywhere from two to six food items per frog two or three times each week. Juvenile frogs should be fed every day.
It is important to use a high quality vitamin and mineral supplement designed for reptiles and amphibians on food before offering it to leopard frogs. This will help avoid nutritional deficiencies which develop overtime when leopard frogs do not receive the right nutrients in their diet. Use the powdered nutritional supplement at every feeding for juvenile frogs and at least once every two or three feedings for adults.