Complex sentence: A large "sea leopard" of approximately 12 feet long and 1100 pounds chased Orde-Lees on the ice and he was only saved when another member of the expedition shot the animal.
Split into simpler sentences: A large "sea leopard" of approximately 12 feet long and 1,100 pounds weight chased Orde-Lees on the ice. He was only saved when another member of the expedition shot the animal.