Another small animal that tigers eat in Ranthambhore (a wildlife park in northern India) is the porcupine  .These animals are spread widely across India in open areas and grasslands; they often live in the earth and between rocks.They are good diggers, and in Ranthambhore are nocturnal  ; they only come out at night.They weigh 12 to 16 kilograms and reach the length of 80 to 90 centimetres.They live usually on vegetables and fruit and seem to have a good sense of smell.Porcupines defend themselves when attacked by moving backwards with their quills upright, often making a strange noise. Several times, I have found the remains of quills where a tiger has killed and eaten a porcupine, but I have never actually seen the kill.In spite of the quills, experienced tigers will try to kill clearly by biting the porcupine's head, its weakest spot.But the quills are very sharp and can give painful injuries to young tigers.If the quills have gone in very deeply or if they are stuck in the tiger's paw, it will try to pull them out.Often, it will be successful, and the wound will get better.But, if the quills have gone in very deeply or if they are stuck in the tiger's neck or mouth, where they cannot be reached, the wound will often turn bad.If this happens, the tiger is in pain and is less able to hunt animals.It has to look for easier prey and so may turn to cows on the edges of the forest.From this, it is a small step to becoming a man-eater. The word "quill" here means    _   .
teeth of a porcupine feathers on a porcupine long, sharp needle-like parts on a porcupine paws of a porcupine