Slow loris

For the denial of service attack, see Slowloris.

Lorises
Nycticebus sp. ?
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Family:	Lorisidae
Subfamily:	Lorinae
Genus:	Nycticebus E. Geoffroy, 1812
Type species
Tardigradus coucang Boddaert, 1785
Species
Nycticebus coucang Nycticebus bengalensis Nycticebus pygmaeus

The slow loris is any one of three species of loris classified in the genus Nycticebus. These slow moving strepsirrhine primates range from Borneo and the southern Philippines in Southeast Asia, through Bangladesh, Vietnam, Indonesia, India (North Eastern India, Bengal), southern China (Yunnan area), Thailand and oddly enough Greece. They are classified as vulnerable or endangered species, and are hunted for their large eyes which are prized for local traditional medicine. The Indonesian name, malu malu, can be translated as "shy one". They are listed as endangered by the U.S. Fish & Wildlife Service.

Physical characteristics

Pygmy Loris female (Nycticebus pygmaeus) clinging to a human arm

Adult slow lorises range in size from 21 to 38 cm, depending on the species, and weigh up to 2 kilograms. The tail is a mere stump, whereas the forelimbs and hindlimbs are of roughly equal length (quadrupedal). The short, thick fur can have a variety of colours, mostly grey-reddish and often with whitish undertones. They have well developed opposable thumbs, which they use to grasp and hold fast to branches, and a very flexible back. A specialized arrangement of blood vessels in the wrists and ankles (rete mirabile) prevents muscle cramps and allows the slow loris to cling for extremely long periods of time. They have a grooming claw on the foot. The eyes are large and point forward and obliquely upward, but color vision is minimal. The ears are small and nearly hidden in the fur. They are generally more strongly built than the slender lorises, and possess a strong sense of smell.

The cranial form of the slow loris follows most of the expectations of the Strepsirhini/Prosimii suborder. To begin, the braincase is low and football/ovaloid like; neither the frontal nor the occipital lobe has expanded much. Furthermore, the frontal suture is visible and the lacrimal is located outside the eye socket. With regards to the eyes’ size, the slow loris' nocturnal behavior results in relatively large eyes. Continuing on, slow lorises have forward facing eyes and postorbital closure, but lack full orbital closure. The spatial relationship between the tympanic ring and the bulla of the slow loris is classified as being attached on the inside. Unlike the majority of other members of the suborder Prosimii, the slow loris does not have inflated bulla. Its foramen magnum is located in a more posterior than vertical position. Moving towards the more anterior aspect of the cranium, there is a separation between the two most mesial incisors that corresponds to the moist rhinarium found in Strepsirhinis. A distinguishing feature between superfamilies Lemuroidea and Lorisoidea is the loris’ relatively short, pipe-like nose, which the slow loris has. Finally, as expected, the splanchnocranium of N. coucang is on the same level as its neurocranium.

As with the cranial form, the dental morphology of the slow loris is consistent with other Strepsirhines. The mandible is V-shaped and is unfused and the dental formula reads 2.1.3.3 / 2.1.3.3. Despite having the same number of teeth, the teeth of the maxilla are arraigned quite differently than those of the mandible. Beginning with the maxilla, as it has already been mentioned that there is a space between the two most mesial incisors and all four incisors are very small. In the mandible, the incisors and the canines are procumbent. The canine’s shape resembles an incisor (incisiform). The lateral connection of these six teeth forms a dental comb. The presence of a dental comb is attributed to three different forms of use: dietary, social, and defense. As a result of the canines’ inclusion in the dental comb, P2 shape changes as well and resembles a canine (caniform). The mandibular condyle of the slow loris is almost on the same level as the occlusal surface of the teeth, which results in the posterior teeth occluding before the anterior teeth. The presence of a glenoid process controls the movement of the mandible. As the slow loris is a frugivoris primate, the cusps of its teeth are low and rounded, not sharp and spiky.

The slow-climbing and arboreal quadruped nature of the slow loris shapes its postcranial anatomy. Moving this way requires a flexible body (lateral flexion and rotation of the vertebral column) with a sturdy grip. The elongation of the lumbar vertebrae aids in creating the flexible body of the slow loris In addition, the scapulas are very laterally located and broad. This helps to facilitate the climbing N. coucang frequently engages in. Since neither its pair of limbs dominates movement, the forelimbs and hind-limbs are approximately the same length; its intermembral index is very close to 1. Two of the most distinct features of all slow lorises are the hands and feet. The hands have broad palms and a pollex capable of 180º adduction from the other digits. Digit II has become significantly reduced, thereby allowing for a wider and stronger grasp. The hands lack interdigital webbing between III, IV, and V, which allows for wide expansion of the digits. The feet are very similar to the hands, except the hallux is larger than the pollex. On the foot there is one claw; all other digits contain nails. These grasping capabilities allow for the climbing and hanging that are characteristic of its movement. the slow loris does have an external tail, but is very short and often covered by fur.

Behavior

Like all lorises, slow lorises are nocturnal and arboreal animals that prefer the tops of the trees, occurring mostly in tropical/subtropical rain forests and bamboo thickets. They have slow, deliberate movements and a powerful grasp that makes them very difficult to remove from branches, especially because they only remove (at most) one limb from the branch at any given moment. They live as solitaries or in small family groups, and mark their territory with urine. Lorises whistle loudly to each other, using a single note, while foraging.

Defense

Slow lorises can produce a toxin which they mix with their saliva and use as protection against enemies. Mothers will lick this toxin onto their offspring before leaving them to search for food. The toxin is produced by glands on the insides of their elbows - the brachial region. The lorises suck it into their mouths and deliver it when they bite or lick. The toxin is not known to be fatal to humans, but causes a painful swelling. If the toxin does not deter a predator, the slow loris will often drop from the branch to the ground and roll into a protective ball.

Feeding

Slow lorises are opportunistic carnivores, typically eating insects, mollusks, lizards, bird eggs, and small vertebrates. With their slow quiet movements, they creep to their prey, in order to catch it with a lightning-quick snatch using both hands. They will also eat fruits and leaves. The metabolic rate is 40% slower than predicted based on size. Slow lorises are not strongly territorial.

Reproduction

Slow lorises are polygamous and breed throughout the year. After an approximately 190-day gestation, the female births one (or rarely two) young, typically limited to one or two litters per year. The newborn clasps itself to the belly of the mother, or occasionally the father. When it is older it will be "parked" on a branch while its parent searches for food. After approximately six to nine months it is weaned. Sexual maturity is achieved around 10 to 24 months. The life expectancy of the slow loris is up to 14 years in the wild and up to 26 years in captivity.

See also

• Venomous mammals
• Sunda Loris

External links

• Slow Loris Research by a toxinologist - includes photos.
• Lemur Center Duke University, USA
• America Zoo general description
• Slow Loris Endangered by BBC World News
• BBC Science and Nature: Slow Loris Loris facts
• Slow Loris and International Animal Rescue by Sydney Morning Herald