Karana needs to make herself weapons to protect herself from the dogs and to kill them to avenge her brother's death.
Karana finds a rock where she can store food until the ship comes in. She does not try to get extra food because she may not need it.
This gave me time to make weapons to protect myself from the dogs, which I felt would sometime attack me, to kill them all, one by one. (ch 8, p. 48)
Karana thinks about the fact that women making weapons is forbidden by her tribe. She goes looking around for weapons that have already been made.
Karana is concerned with the wild dogs. They are part of a pack that roams the island, having become wild after their owners died. They are fierce and dangerous. When Karana is alone with Ramo, the wild dogs often come at night. After they killed Ramo, she became both afraid of them and out to get revenge.