Northern Leopard Frog
Northern Leopard Frog
Frogs are amazing animals. Despite their fragile appearance and inoffensive ways, they have ingenious strategies to survive in the most severe climates our planet has to offer. We have an amazing frog living just outside our doors; perhaps you have encountered this little guy before? You could be out for an afternoon walk when suddenly, in a blink of an eye, you catch a glimpse of green jumping into the bushes in front of you. This is probably none other than the Northern leopard frog.
Northern leopard frogs are named because of irregularly shaped dark spots that cover their backs and legs. Their bodies can be green or brown with prominent folds of skin running down each side of the back and have a white or yellowish-tinged underbelly. The body length of the species can sometimes exceed ten centimetres, but large individuals are quite rare; adults are typically five to nine centimetres. A similar species in appearance to the leopard frog is the pickerel frog, which has brown or tanned skin and angular shaped dark spots usually arranged in two rows along their backs. You can however, tell the difference between the species as pickerel frogs are never green.
These amphibians can be found in a wide range of habitats, from prairie to woodland to tundra regions. They generally live near ponds and marshes, but will often venture into well covered grasslands and gardens. You may also find them hopping across roads and trails as they can be found considerable distances from water.
Leopard frogs eat a variety of small invertebrates including crickets, beetles, flies, and smaller frogs, (including their own species) and they will even eat small snakes and birds. To catch their meals they must wait patiently until they can pounce on it using their strong legs.
The truly fascinating part about leopard frogs is how they hibernate through the cold winter season. In the fall, leopard frogs must find a suitable living place (hibernaculum) where it can be protected from winter weather and predators. Its metabolism slows down drastically, so it can winter by utilizing its body’s energy stores. Frogs are ectothermic, which means they lack internal sources of heat and rely on the environment to regulate their body temperatures. Birds and mammals, including humans, are endotherms. We generate heat internally through metabolic reactions. An advantage that ectotherms have over mammals is that they can survive long periods of time without eating, such as the hibernation period. Aquatic frogs typically hibernate underwater, but a common misconception is that they bury themselves into the mud, which would actually suffocate them if they remained buried for an extended period of time. They must be near oxygen rich water and spend a good portion of the winter lying just on top of the mud or partially buried where they can take in oxygen through their skin. They may even swim around from time to time. If the pond or stream were to freeze to the bottom, the frog would suffocate and die.
Once winter is over and spring arrives, leopard frogs will begin looking for a mate. They breed in mid- to late spring in relatively permanent bodies of water, but most often in wetlands without large fish. The female can lay up to 7000 eggs, which become attached submerged vegetation. The eggs are approximately 1.5 mm in diameter and hatch in one to three weeks, depending on the temperature. Tadpoles begin to transform in mid-to late summer. In the wild, individuals live for four or five years, while in captivity they can live up to nine years.
The Northern leopard frog in is currently listed as “Not at Risk” under the Ontario Endangered Species Act of 2007, and the International Union for Conservation of Nature lists the global status as Least Concern. The species status was confirmed in 2010. However, this does not mean that it will always remain as such. The main threats to leopard frogs in Ontario are habitat loss and degradation, increased predation and road mortality. Overexploitation such as harvesting for school dissections has also been a threat to this species. Despite these threats, the Northern leopard frog’s high mobility and use of a wide range of habitats are helping to prevent an overall species decline.
I’m sure you’re wondering how you can help leopard frogs and other reptiles and amphibians that live in our province, and there are certainly many ways you can help. Reducing road mortality is the main concern for the safety of our animals. You can also report any observations of reptiles and amphibians to the Ontario Reptile and Amphibian Atlas. This program helps to protect our biodiversity as they use the information provided to get a better understanding of which species need more help.
Kids for Turtles would like to remind you that it is turtle hatching season! Early this year, we placed several metal wire cages on nests in the area to protect the eggs from predators. This is to help increase the survival rate of hatchlings! If you have a nesting cage or are aware of a turtle nest in your area, please ensure that you are monitoring it daily and recording things such as species, number of hatchlings and in which general area they were heading as they left the nest. All of this information can be used by Kids for Turtles to get a better idea of the populations in our area and therefore better inform us of how we can help.
Michael Norman is the Office Coordinator for the summer of 2014.