Also known as the Golden Barrel cactus or, rather amusingly as the "Mother in law's pillow".
In their natural habitat of Mexico, these plants were the focus of an intensive rescue mission in the Rio Moctezuma Valley when the dam construction was underway and the area was to be flooded. Luckily, a Mexican botanical garden hurried to remove these and other rare plants - thus enabling conservation.
Older specimens tend to be oblong shaped and lean towards the south or south-west so that the spines give the body of the plant protection from the harsh desert sun. In fact, desert travellers can use the plant as a compass.