As massive quadrupeds, sauropods developed specialized "graviportal" (weight-bearing) limbs. The hind feet were broad, and retained three claws in most species. Particularly unusual compared with other animals were the highly modified front feet ("manus"). The front feet of sauropods were very dissimilar from those of modern large quadrupeds, such as elephants. Rather than splaying out to the sides to create a wide foot as in elephants, the manus bones of sauropods were arranged in fully vertical columns, with extremely reduced finger bones (though it is not clear if the most primitive sauropods, such as "Vulcanodon" and "Barapasaurus", had such forefeet). The front feet were so modified in eusauropods that individual digits would not have been visible in life.