In wet, poorly drained areas such as along the Caribou Plain trail, black spruce and larch live in a thick sphagnum moss carpet. Some of these stunted trees have lived here for more than a century, yet are no taller than a person. A lack of nutrients in naturally acidic soil is a major constraint to their growth. Some bog plants have found ways to supplement their meagre diets by catching and consuming insects. Three species of insectivorous plants may be seen at Caribou Plain bog; they are the pitcher plant, sundew and bladderwort.
The shallow waters of ponds and streams surrounding the bog support much animal life. At dusk or dawn, moose and beaver become active, feeding on succulent yellow pond lilies. Although the bog pond is too acidic for most frog and fish eggs to hatch, many adult frogs can be seen in and near the pond.