Dachshunds have a wide variety of colors and patterns, the most common one being red. Their base coloration can be single-colored (either red or cream), tan pointed (black and tan, chocolate and tan, blue and tan, or isabella and tan), and in wirehaired dogs, a color referred to as wildboar. Patterns such as dapple (merle), sable, brindle and piebald also can occur on any of the base colors. Dachshunds in the same litter may be born in different coat colors depending on the genetic makeup of the parents. The breed is prone to spinal problems, especially intervertebral disk disease (IVDD), due in part to an extremely long spinal column and short rib cage. The risk of injury may be worsened by obesity, jumping, rough handling, or intense exercise, which place greater strain on the vertebrae. About 20–25% of dachshunds will develop IVDD.