Chad says, "Whats the big deal about the Milkweed plant?" Manny replies, "Big deal...my siblings are eating on the milkweed. It is the only plant that the monarch caterpillars can eat. The milkweed plant contains toxin that the caterpillars can digest. The toxins make the monarch butterfly poisonous to other predators. So, animals and birds will not try to eat the monarch butterflies!"