Tropical forests are increasingly degraded by industrial logging, urbanization, agriculture and infrastructure, with only 20% of the remaining area considered intact. However, this figure does not include other, more cryptic but pervasive forms of degradation, such as overhunting. In this seminar I will discuss how to quantify and map the spatial patterns of mammal defaunation in the tropics using empirical data on mammal abundance declines from local hunting studies. I will also argue how, according to our projections, half of (seemingly) intact tropical forests are partially devoid of large mammals, and how forest coverage alone is not necessarily indicative of ecosystem intactness. Further, I will show how the combination of satellite-based land-cover change maps, habitat suitability models and hunting pressure models can be applied to quantify the individual and combined effects of habitat loss and hunting pressure on mammal communities. I will finish the seminar discussing how changes in the abundance of mutualists (seed dispersers) and antagonists (seed predators and herbivores) may impair ecosystem functioning in tropical forests by altering the structure and composition of tropical forests and, eventually, their carbon storage capacity.