A lemur that moved like a sloth
In the limestone caves of northern Madagascar's Ankarana Massif, paleontologists in 1988 found the nearly complete skeleton of Babakotia radofilai, an extinct, medium-sized lemur. This creature was a member of the Palaeopropithecidae family, a group commonly known as sloth lemurs due to their remarkable convergent evolution with modern tree sloths. Babakotia weighed between 16 and 20 kilograms and was built for a life of slow, deliberate climbing and suspension. Its anatomy shows a fascinating mix of features: long forearms, curved fingers, and mobile hip and ankle joints, all adaptations for hanging and moving through trees.
The discovery of Babakotia helped clarify the evolutionary relationships among Madagascar's extinct primates. It represents an intermediate form between the smaller, more agile sloth lemurs like Mesopropithecus and the larger, more suspensory ones like Palaeopropithecus. Analysis of its skeleton suggests it was a slow climber, similar to a loris, but also engaged in sloth-like hanging behaviors. This evidence indicates that the ancestors of modern indriids—the leaping lemurs we see today—were likely slow climbers and hanging feeders, and that the high-speed leaping of their descendants evolved much later. Its diet consisted mainly of leaves, supplemented with fruits and hard seeds.