AFRICAN GALAGOS AND ASIAN LORISES
One of the main differences between the galagos and lorises and the lemurs is their geographical distribution. Galagos and lorises live in mainland Africa and Asia. Lemurs are confined to Madagascar. Other differences are unapparent and morphological for example the structure of the carotid artery.
Galagos and lorises are interesting in that the two groups have developed very different approaches to a nocturnal, arboreal way of life. They live in very different habitats and move in very different ways. Their different diets, ways of obtaining food and evading predators are determined by the different ways they move. Being nocturnal they do not compete with monkeys as monkeys are diurnal.
Lorises – the name is Dutch for clown –are renowned for moving very slowly and smoothly. They are highly specialised morphologically to climb in trees or cling to branches having fore and hind limbs of equal length and very short tails. They practice ‘cryptic locomotion’ by moving extremely slowly through thick vegetation which hides them from predators. If alarmed, they may freeze remaining immobile for hours and even days or just fall into the forest below. These animals have to live in thick vegetation which can conceal them from view if this approach to avoiding predators is to succeed. Lorises have a territorial social system whereby a male’s territory may overlap the territories of many females. Unlike female galagos, female lorises do not form groups of related females. Lorises feed on fruits and gum and slow-moving prey which they find by smell. Although the insects they feed on are easy to find by smell, many are irritant and unpalatable and lorises must be adapted to survive the ingestion of the irritants and toxins these insects produce.
1 and 2. Adult and skeleton of Loris tardigradus. The slow loris lives in the tropical forests of West India and Sri Lanka. The adult show the typical appearance of a loris: large eyes, short snout, legs of equal length and no tail. The skeleton shows how the animals climb.
3. Skeleton of Nycticebus coucang. The slender loris lives in Vietnam and Borneo. This species has a very mobile hip joint for climbing; its opposable first digit on hand and foot are used to grip branches strongly. It has no tail. This specimen must have suffered a broken thigh at one time: the limb has healed but the bone where the limb broke is very thick.