Pups will vocalize when stressed or when prodding their mothers to allow them to suckle. Pups are weaned by a year but can continue to suckle for another year. Calves may be allowed to suckle from females other than their mothers. A foal is usually weaned at around 11 months, but may suckle for longer. Cows may be made to suckle calves in a crush. One scene required the baby to suckle Chan's nipple. The need to suckle is instinctive and allows newborns to feed. Likewise, calves may suckle for only a month or as long as a year. For this reason, the cria must suckle frequently to receive the nutrients it requires. The main symptoms were stiffness, inability to rise, and failure to suckle in newborns. However, there are situations when a mother cannot suckle her own baby. She sent a female bear to suckle the baby, who was then raised by hunters. This means that the anencephalics move, smile, suckle and breathe without the aid of devices. They suckle on land when the mother leaves the water. Females suckle their young every other day, and neglect their young as long as possible.