In the middle of Rio de Janeiro sits the world’s largest urban rainforest: Tijuca National park. To combat a century of deforestation and hunting, a team of researchers are repairing the forest’s forgotten web of life, one species at a time.

Trees and habitat are often the focal point of any conservation strategy, but here in Brazil, the missing link to a thriving forest is the animals.

After withstanding a century of deforestation and hunting, Tijuca is incomplete without its animals and needs researchers to identify what’s missing in the secret web of life. From a canopy of swinging howler monkeys to the nut-cracking jaws of the lovable agouti, researchers are using breakthrough science to bring fauna back. New seedlings are one of many signs that the reintroductions are working, restoring the forest to its full potential and reconnecting the life sustaining bonds between plants and animals.