About two to three months before birth, the calf sheds a fine white layer of soft fetal hair called the lanugo. Within days or weeks, the calf becomes more robust. Its fur turns reddish-brown to tawny within one to two weeks. Calves shed and replace their natal coat when they are one or two months old. This first molt is usually completed by August.
Calves then molt annually.
F. Care of the Young. Calves may nurse for as long as two years. Some may nurse even longer, if the mother does not have a new calf. The composition of milk remains relatively constant throughout the nursing period. Nursing usually takes place in the water, but sometimes occurs on ice or land.