Grenouille des marais— Quebec wildlife

The pickerel frog (Lithobates palustris, formerly Rana palustris) is a small North American frog, characterized by the appearance of seemingly "hand-drawn" squares on its dorsal surface.

Habitat and range

Pickerel frogs have varied habitats, the northern populations prefer to live near cold, clear water. They prefer rocky ravines, bogs and meadow streams, but can be found around lakes and rivers that are heavily wooded. In a study on amphibians in Canada, pickerel frogs were negatively associated with young forest stands. Pickerel frogs in the southern portion of their range prefer warmer waters, like those of the Coastal Plain and floodplain swamps. They are seen most often along the edges of streams, lakes, rivers, and even flooded ditches. During the winter months they will hibernate under the silt and debris in their aquatic environments; they are usually only active from April to October. When feasible, this species utilizes caves for thermal refugia during the coldest months of the year. The pickerel frog is a trogloxene species, meaning they occur in caves, but are unable to complete their life cycles there. Though they are most abundant in caves during the winter, they are active deep within caves at almost any time of year. When temperatures get too cold, this species will inhabit hibernacula. These hibernacula are commonly found nearby one another in the center of the cave. Pickerel frogs will sometimes inhabit those same caves during hot summers.

Diet

The pickerel frog's diet consists of ants, spiders, various bugs, beetles, sawfly larvae, and other invertebrates. In order to catch their prey pickerel frogs will often search grassy areas next to bodies of water.

Reproduction

Pickerel frogs typically emerge from hibernation around the end of March with the majority of the frogs arriving at breeding ponds by early May. No fall reproduction has been reported for this species. At the ponds, pickerel frogs are usually observed in large groups in the water. Mating behavior is not much different from other ranids. The males initiate breeding by emitting their low pitched call; this call is usually so low pitched that it is often not heard during calling surveys. Males can alter their call type based on interactions with other males. Males are known to call while submerged, although this is often inaudible in the air. Calls underwater vary among populations, suggesting that under certain circumstances it is better to vocalize underwater than into the air. Frogs reproduce by external fertilization while engaging in a behavior called amplexus; sometimes amplexus will last more than a day or two, even after the female has deposited the eggs. During the breeding season, males tend to lose body mass (with larger males losing more than smaller males).