A dose’s effectiveness is dependent on a dingo’s mass, which led Letnic to test the idea that 1080 use might be related to dingoes’ size change. Kangaroo numbers increase when dingo populations are controlled, so the combination of extra prey availability and reduced competition may make it easier for dingoes that aren’t killed by the poison to find food and grow. “By reducing the dingo population, [1080 is] changing the environment that dingoes are growing up in,” Letnic says.