 The skin of salamanders , in common with other amphibians , is thin , permeable to water , serves as a respiratory membrane , and is well @-@ supplied with glands . It has highly cornified outer layers , renewed periodically through a skin shedding process controlled by hormones from the pituitary and thyroid glands . During moulting , the skin initially breaks around the mouth , and the animal moves forwards through the gap to shed the skin . When the front limbs have been worked clear , a series of body ripples pushes the skin towards the rear . The hind limbs are extracted and push the skin farther back , before it is eventually freed by friction as the salamander moves forward with the tail pressed against the ground . The animal often then eats the resulting sloughed skin . 
