For a human mother-to-be, nine months of pregnancy may feel endless, but we still have it better than some members of the animal kingdom. Giraffes remain pregnant for 13 to 16 months—and not only that, they also give birth standing up, welcoming the baby into the world with a drop of 5 to 7 feet to the ground. Elephants experience pregnancy on an even larger scale, with the calf spending enough time in the womb to celebrate a second birthday before ever taking a breath. The longest vertebrate pregnancy, however, belongs to the frilled shark. One of several ancient species referred to as “living fossils,” this deep sea dweller can be gestate its young for 3.5 years before giving birth.