Goliath birdeater spider - Imagine a spider as big as a child's forearm that weighs as much as a puppy. That's how huge the South American Goliath birdeater — arguably the world's largest spider — can be!
Giant tarantulas keep tiny frogs as pets. Insects will eat the burrowing tarantulas’ eggs - so the spiders protect the frogs from predators, and in return the frogs eat the insects. Ecologists categorize this interaction as symbiotic mutualism.