Complex sentence: There are many more western lowland gorillas than the eastern variety; compared to a possible total of over 100,000 western lowland gorillas, there are only about 5,000 eastern lowland gorillas in the wild, and only a single female in captivity at the Antwerp Zoo in Belgium.
Split into simpler sentences: There are many more western lowland gorillas than the eastern variety; compared to a possible total of over 100,000 western lowland gorillas, there are only about 5,000 eastern lowland gorillas in the wild. Outside the native range, only a single female is in captivity at the Antwerp Zoo in Belgium.