qT=1&tQ=The African acacia trees pass along warnings to other acacia trees when this animal comes to eat. Which animal is it?&tC=Giraffe|Ostrich|Zebra|Elephant&cC=1&fB=A giraffe will eat the leaves off the acacia tree, so the tree has learned to protect itself by producing poisonous alkaloids. The giraffe only gets a couple of mouthfuls of leaves before the remaining leaves become inedible.<br><br>When an giraffe comes to feed off one tree, that tree emits ethylene into the air up to 50 yards that warns other acacia trees to step up alkaloid production.