Loris lydekkerianus Cabrera, 1908

Taxonomic Identification

Loris lydekkerianus Cabrera, 1908 (gray slender loris) is a slender loris, with all members of this group having extremely gracile limbs and extreme stereoscopic vision.

Pelage Variation

Gray slender lorises show wide variation in pelage (fur) color, and each subspecies can be identified by this variation.

Dorsal Fur Characteristics

Their fur is short and gray or reddish on the back; sometimes a darker stripe extends from the top of the head to the end of the back.

Ventral Fur Characteristics

The ventrum (underbelly) is white or buff-colored.

Eye and Orbit Structure

The eyes are surrounded by darker fur, their orbits face straight forward to produce excellent stereoscopic vision, and the eyes are positioned closer together than in any other primate.

Facial Markings

Between the eyes there is a white patch of hair called the median stripe.

Muzzle Structure

The muzzle is larger and less pointed than that of the red slender loris.

Hand Specializations

The hands are highly specialized with a reduced second digit that allows the loris to cling to small branches.

Grasp Adaptations

This ability is further enhanced by adaptations in the first metatarsal that are thought to enable an extremely firm grasp.

Tail Structure

The tail is vestigial.

Body Size

Average head-body length is 18–26 centimetres (7.1–10.2 in).

Sri Lankan Subspecies Morphology

For Sri Lankan subspecies, Loris lydekkerianus grandis has short ears and a heart-shaped face.

Subspecies Ventral Hair Differences

The basal ventrum hairs of Loris lydekkerianus grandis are black, while those of Loris lydekkerianus nordicus are white.

Overall Distribution Range

Gray slender lorises are found in southern India and Sri Lanka.

General Habitat

They inhabit primary and secondary rainforest, dry semi-deciduous forest, and montane cloud forest up to 2,000 metres (6,600 ft) above sea level.

South-western India Range

In south-western India, their range lies roughly between the Tapti and Godavari Rivers, extending down to the south coast of the subcontinent.

Subspecies Geographic Separation

The subspecies are geographically separated.

Malabar Gray Slender Loris Distribution

In south-western India, the Malabar gray slender loris occurs in the wet forests of the Western Ghats in the states of Karnataka, Kerala and Tamil Nadu up to an altitude of 1,200 metres (3,900 ft).

Mysore Gray Slender Loris Habitat

The Mysore gray slender loris inhabits the tropical dry forests of the Eastern Ghats in the states of Andhra Pradesh, Karnataka and Tamil Nadu, and is common in open Euphorbia scrub forests and on Acacia trees at an altitude of 300–500 metres (980–1,640 ft).

Mysore Slender Loris Additional Range

It can also be found on the dry eastern slopes of the Western Ghats.

Mating System

Gray slender lorises are promiscuous: multiple males compete for one female for mating.

Mating Periods

Mating occurs biannually, in April–June and October–December.

Estrus Cycle Details

Although mating occurs twice a year, lorises can only breed once a year, as one estrus cycle will fail and another will begin approximately 2 weeks after the failed cycle.

Gestation Length

Gestation is approximately 170 days.

Offspring Frequency

Twins are very common among this species.

Reproductive Physiology

The reproductive tract and ovarian cycle follow the general mammalian pattern.

Lactation Adaptations

For lactation, four teats develop and produce milk before the infant is born.

Post-birth Female Behavior

After giving birth, females are not receptive to males and focus on caring for their young.

Reproductive Rate

The reproductive rate of the gray slender loris is among the lowest of any primate weighing under 500g.