It later kills several zebra and wildebeest. The striking stripes make it resemble a zebra. Zebrawood is characterized by a striped figure that is reminiscent of a zebra. The hyena kills the zebra and later the orangutan. Only the mountain zebra lacks a dorsal stripe. The quagga was the southernmost distributed plains zebra, mainly living south of the Orange River. Its design differs significantly from GNU Zebra and Quagga. A 2005 genetic study confirmed the quagga being the same species as the plains zebra. These zebra/donkey hybrids are very rare. Chlorine dioxide may be used for control of zebra and quagga mussels in water intakes. Invasive species are a problem for Lake Ontario, particularly lamprey and zebra mussels. Zig-zag lines are used on both ends of zebra crossings. Other hybrids include the zorse, a cross between a zebra and a horse. Note that the zebra and cat still maintain homeostasis in all states. The Cape mountain zebra was hunted to near extinction.