the second molar. Slow lorises range in weight from the Bornean slow loris at to as much as for the Bengal slow loris. Slow lorises have stout bodies, and their tails are only stubs and hidden beneath the dense fur. Their combined head and body lengths vary by species, but range from between all species. The trunk is longer than in other living strepsirrhines because they have 15–16 thoracic vertebrae, compared to 12–14 in other living strepsirrhines. This gives them greater mobility when twisting and extending towards nearby branches. Their other vertebrae include seven cervical vertebrae, six or seven lumbar vertebrae, six or seven sacral vertebrae, and seven to eleven caudal vertebrae. Unlike galagos, which have longer legs than arms, slow lorises have arms and legs of nearly equal length. Their intermembral index (ratio of arm to leg length) averages 89, indicating that their forelimbs are slightly shorter than their hind limbs. As with the slender lorises, their arms are slightly longer than their body, but the extremities of slow lorises are more stout. Slow lorises have a powerful grasp with both their hands and feet due to several specializations. They can tightly grasp branches with little effort because of a special muscular arrangement in their hands and feet, where the thumb diverges at nearly 180° from the rest of the fingers, while the hallux (big toe) ranges between being perpendicular and pointing slightly backwards. The toes have a large flexor muscle that originates on the lower end of the thigh bone, which helps to impart a strong grasping ability to the hind limbs. The second digit of the hand is short compared to the other digits, while on the foot, the fourth toe is the longest. The sturdy thumb helps to act like a clamp when digits three, four, and five grasp the opposite side of a tree branch. This gives their hands and feet a pincer-like appearance. The strong grip can be held for hours without losing sensation due to the presence of a rete mirabile (network of capillaries), a trait shared among all lorises. Both slender and slow lorises have relatively short feet. Like nearly all lemuriforms, they have a grooming claw on the second toe of each foot. Slow lorises have an unusually low basal metabolic rate, about 40% of the typical value for placental mammals of their size, comparable to that of sloths. Since they