Like we said earlier, those species that are likely to become endangered are classified as vulnerable species. Sadly, the list of vulnerable monkeys is nearly as long as that of the endangered species. So, if proper conservation measures are not implemented at the earliest, the list of endangered species will become twice as long in the near future. Of late, environmentalists have noticed that the population of quite a few species is on a decline. What is more disturbing is the rate at which their number has been declining over the last decade or so. In most cases, the decline can be primarily attributed to the following factors. Excessive Hunting Several monkey species, including the Roloway and Pennant's Red Colobus found in Africa, are excessively hunted for their meat. On the other hand, species like the Miss Waldron's Red Colobus and Mt. Uarges Guereza―a subspecies of Mantled Guereza―are hunted extensively for their skin, which has a great demand in the international market. Loss of Habitat Human encroachment has resulted in destruction of habitat for several monkey species. Illegal logging, land clearance for agriculture, expanding human settlements, and other such factors are causing their natural habitat to deplete at an alarming rate. While habitat loss leaves them homeless and vulnerable, fragmentation of habitat makes it difficult for them to breed. Other Factors It may come as a surprise, but the practice of killing monkeys for the use of their various body parts in traditional medicine continues unabated even today. Also on rise is the practice of keeping them as pets. In a bid to capture these monkeys for pet trade, hunters use snares, which leave them injured―if not trapped, eventually resulting in their death. Going by the rate at which this list is growing, it wouldn't be long before we witness many more extinctions. If the aforementioned factors responsible for the decline in monkey population are not curbed soon, these species, which feature in the endangered monkeys list as of today, will soon be added to the list of the extinct animals, thus leaving the planet devoid of some of the most interesting members of kingdom Animalia.