Bronx Zoo, New York City (No. 45)

Silvery lutungs are diurnal, and travel in groups of around 9-40 individuals with one adult male and many adult females communally caring for infants. They rarely leave the trees, which provide them protection from ground-dwelling predators, and rapidly flee if threatened. Each group occupies a home range of 20 to 43 hectares (49 to 106 acres), although these may overlap with those of neighbouring groups. During the day, individuals may travel up to 500 metres (1,600 ft) through the forest, with some forming all-female subgroups that separate from the group containing the male. The entire group shelters in a single tree at night. 

The social structure of silvery lutungs is matrilineal and harem based. Females remain in the group for life, while males leave shortly after reaching adulthood, living in small groups of their own until they can take over an established harem. Within the group, males dominate the females, and females with young dominate those without. However, there is relatively little aggression within the group compared with some related species.

Because group ranges often overlap, different groups frequently come into contact with one another. The adult male protects his group and territory from competing males, communicating his dominance to other males via vocalizations and fighting. In the absence of males, however, females from different groups are more likely to interact peacefully. The most serious conflicts occur when a male intrudes directly on the territory of another male, which may result in the intruder displacing the resident and taking control of the group. In many other primates, such a displacement would normally be followed by the male killing any infants sired by his predecessor; although this may occur in silvery lutungs, it has not been directly observed, and may be less common than in some other species. 

Although less vocal than other closely related species, silvery lutungs make at least thirteen different vocalisations, with the most common being used by adult males defending their territory. Other vocalisations express fear, anger, excitement, and satisfaction, in addition to various calls made by infants.

Bronx Zoo, New York City (No. 42)

The Amur leopard (Panthera pardus orientalis) is a leopard subspecies native to the Primorye region of southeastern Russia and northern China. It is listed as Critically Endangered on the IUCN Red List. In 2007, only 19–26 wild leopards were estimated to survive in southeastern Russia and northeastern China. It was considered as one of the rarest cats on Earth. 

As of 2015, fewer than 60 individuals were estimated to survive in Russia and China. Camera-trapping surveys conducted between 2014 and 2015 revealed 92 individuals in an 8,398 km2 (3,242 sq mi) large transboundary area along the Russian-Chinese border. In 2019, it was reported that the population is close to 90 leopards. 

Results of genetic research indicate that the Amur leopard is genetically close to leopards in northern China and Korea, suggesting that the leopard population in this region became fragmented in the early 20th century. The North Chinese leopard was formerly recognised as a distinct subspecies P. p. japonensis, but was subsumed under the Amur leopard in 2017.

The Amur leopard differs from other leopard subspecies by its thick fur that is pale cream-colored, particularly in winter. Rosettes on the flanks are 5 cm × 5 cm (2.0 in × 2.0 in) and widely spaced, up to 2.5 cm (0.98 in), with thick, unbroken rings and darkened centers. Its fur is fairly soft with long and dense hair. The length of hair on the back is 20–25 mm (0.79–0.98 in) in summer and up to 70 mm (2.8 in) in winter. The winter coat varies from fairly light yellow to dense yellowish-red with a golden tinge or rusty-reddish-yellow. In summer, the fur is brighter with more vivid coloration pattern. It is rather small in body size, with males larger than females. Males measure from 107–136 cm (42–54 in) with an 82–90 cm (32–35 in) long tail, a shoulder height of 64–78 cm (25–31 in), and a weight of 32.2–48 kg (71–106 lb). Females weigh from 25–42.5 kg (55–94 lb). 

The North Chinese leopard was first described on the basis of a single tanned skin which was fulvous above, and pale beneath, with large, roundish, oblong black spots on the back and limbs, and small black spots on the head. The spots on the back, shoulders and sides formed a ring around a central fulvous spot. The black spots on the nape were elongated, and large ones on the chest formed a necklace. The tail was spotted and had four black rings at the tip.

Bronx Zoo, New York City (No. 41)

Matschie's tree-kangaroo (Dendrolagus matschiei), also known as the Huon tree-kangaroo is a tree-kangaroo native to the Huon Peninsula of northeastern New Guinea island, within the nation of Papua New Guinea.

Under the IUCN classification, Matschie's tree-kangaroo is an Endangered species.

The scientific name honours German biologist Paul Matschie.

With a body and head length of 20 to 32 inches (51–81 cm), Matschie's tree-kangaroo are much smaller than Australia's well-known red kangaroo. An adult male weighs between 20 and 25 lb (9–11 kg). An adult female weighs between 15 and 20 lb (7–9 kg)

There is no particular season in which they breed. Gestation lasts 44 days and joeys of captive bred individuals leave the pouch after 11 months. The average life span of the Matschie's tree-kangaroo in the wild is unknown, but is at least 14 years. The life span of the kangaroo in a zoo is about 20 years.

The most distinctive trait of all tree-kangaroos is the hair whorl they possess. It is a patch of hair that goes out in many directions and its location ranges from up near the shoulders all the way down to the tail. The Matschie's tree-kangaroo is golden on its ventral side, lower parts of its limbs, ear edges, belly, and tail, and the rest of its body is a chestnut brown colour, except for usually having a dark stripe down its back. Their faces are typically an array of yellow and white colours. The Matschies’ are similar in colour and size to Dendrolagus dorianus, the Doria's tree-kangaroo. Matschies’ ears are small and bear-like looking and they do not have a good sense of hearing because of it. They have curved claws on their forelimbs and soft pads on their hind limbs that aid in their climbing ability, and they have some independent movement of their digits as well as good dexterity due to their forelimbs being able to bend a great deal. The 4th and 5th digit of their feet are enlarged, the 1st digit is absent, and the 2nd and 3rd digits are syndactylous (two digits that look like one fused together). Scientists have discovered that the Matschie's are able to walk bipedally and there's a lot of rotation in their limbs for climbing. Out of all of the Dendrolagus species, the Matschie's tree-kangaroo is the best vertical climber and has more strength in its muscles than any others. Their tails help to offset their balance while moving swiftly through the trees since their tails are about the same length as their head and body size. Sexual dimorphism is very low, with males and females being of about equal sizes. The upper and lower jaws of the Matschie's tree-kangaroos are different too in addition to them being different in body size. The upper jaw has three incisors, one canine, one premolar, and four molars, while the lower jaw has one very sharp incisor, no canines and low crowned molars.

Bronx Zoo, New York City (No. 44)

The silvery lutung (Trachypithecus cristatus), also known as the silvered leaf monkey or the silvery langur, is an Old World monkey.  It is arboreal, living in coastal, mangrove, and riverine forests in Peninsular Malaysia, Sumatra, and Borneo.

It is the type of its species group. 

The silvery lutung is a medium-sized monkey with a long, non-prehensile tail. It has grey-tipped, dark brown or black fur, giving it a uniform silvery appearance. Unlike some related species, there are no paler markings on the face or body, except for a patch of whitish hair on the groin of females. A crest of fur runs along the top of the head, and the hair on the cheeks is long, often obscuring the ears. The hands and feet are hairless, with dark coloured skin, and have opposable thumbs and toes. 

Females range from 46 to 51 centimetres (18 to 20 in) in head-body length, with an average weight of 5.7 kilograms (13 lb) and a tail length of 67 to 75 centimetres (26 to 30 in). Males are slightly larger, from 50 to 58 centimetres (20 to 23 in) in length, with an average weight of 6.6 kilograms (15 lb) and a tail length of 67 to 75 centimetres (26 to 30 in). 

Like other langurs, the silvery lutung has a large three-chambered stomach to digest the cellulose found in its herbivorous diet. This allows for fermentation of food, and has some similarities with the stomach of ruminants. The intestine is unusually long, even compared to those of other langurs, and has a number of pouches along its length, which carry out further fermentation of plant matter. The teeth have grinding ridges and other modifications to allow the more efficient processing of tough leaves.

The silvery lutung is found across Borneo and Sumatra, as well as in parts of the south-western Malay peninsula, the Natuna Islands, and other nearby islands. It inhabits mangrove swamps and nearby forest regions, and generally avoids travelling far from coasts or rivers.