Humans killed off the giant birds by overhunting, a new study says, although the hunters did not use bows and arrows. (sciencemag.org)
These threats include overhunting of the bears and oil spills. (natureworldnews.com)
«We show that dense - wooded, large - seeded Amazonian tree species are replaced by light - wooded trees that produce smaller seeds, which continue to be dispersed in overhunted forests by more resilient smaller mammal and bird species.» (sciencedaily.com)