The strings of eggs absorb water and swell in size. Small tadpoles hatch out after two to three weeks. At first they hold onto the remains of the strings and feed on the jelly. They later attach themselves to the underside of the leaves of water weed before becoming free swimming. The tadpoles look like those of the common frog ("Rana temporaria"). They are a darker colour, being blackish above and dark grey below. They can be told apart from the tadpoles of other species by the fact that the mouth is the same width as the space between the eyes, and this is twice as large as the distance between the nostrils. Over a few weeks their legs develop and their tail slowly gets reabsorbed. By twelve weeks of age, they are small toads measuring about long and ready to leave the pond.