Not all lorises are slow: rapid arboreal locomotion in Loris tardigradus of Southwestern Sri Lanka

Abstract

The unique slow-climbing quadrupedalism of Asian lorises has been the subject of numerous studies; however, qualitative observations of more rapid locomotion have occasionally been reported. Field studies of the red slender loris have revealed the habitual use of unexpectedly high-speed locomotion by the so-called "sloth of the primate world." Novel video footage permitted the first quantitative kinematic analysis of rapid quadrupedalism in wild lorises. Observations revealed that this previously unexplored behavior is far from infrequent, with 26% of red slender loris locomotor activity being dedicated to high-velocity arboreal quadrupedalism. This locomotor pattern may represent a primitive retention of the rapid, scrambling quadrupedalism that is observed in other strepsirhines, or it may constitute a more recent specialization of this smallest loris taxon.

Perch size and structure have species-dependent effects on the arboreal locomotion of rat snakes and boa constrictors

“…Highly arboreal limbed animals such as lorises, chameleons and twig anoles often move slowly, but depending on the context for their movement some bursts of faster locomotion may occur (Peterson, 1984;Irschick and Losos, 1998;Nekaris and Stevens, 2007). Similarly the locomotion that we observed for snakes on the thin horizontal cylinders was extremely slow, especially the arboreal lateral undulation of the boa constrictors on the wire.…”

The effect of branch diameter on primate gait sequence pattern

“…Lemurids (Eulemur fulvus and Eulemur rubriventer) are adept arborealists, some of which spend nearly all of their time moving through the continuous canopy [e.g., Sussman, 1977]. Lorisids (Nycticebus coucang and Loris tardigradus) are a derived group, with the relatively longest limbs of all primates and specializations for deliberate walking and agile climbing [Curtis, 1995;Ishida et al, 1983;Jouffroy et al, 1983;Nekaris & Stevens, 2007;Runestad, 1997].…”

Extreme primates: Ecology and evolution of Asian lorises

“…Intriguingly, most captive examinations of this remarkable locomotor pattern have been made of single animals in a small cage or animals moving on a single pole, either urged forward with rewards or encouraged to move freely in this unnatural situation (but see Nekaris and Stevens for animals offered multiple substrates). Although these studies have built a picture in which lorises can move quickly and even “race‐walk” up to 1.65 m/sec, and help us to understand loris gait kinematics, they bear little resemblance to what a wild loris looks like when it moves.…”