Posted by: Rebecca Whitham, Communications The giraffe calf has grown nearly a foot since his birth 3 weeks ago, towering in at just about 7 feet tall now. But there’s another tell-tale sign of growth to look for: the formation of the calf’s ossicones. Notice mom’s fully formed ossicones and the little ones just starting to take shape on baby’s head. Photo by Dennis Dow/Woodland Park Zoo. Ossicones are the horn-like protuberances giraffes sport on their heads. They are formed from ossified cartilage (cartilage that has transformed into bone) and covered in skin and fur. Remember what looked like a little tuft of hair on baby when he was first born? One-day-old giraffe with flat ossicones. Photo by Ryan Hawk/Woodland Park Zoo. Those were his little ossicones, all flat and barely developed. But over the weeks they have begun to harden. You can see in these pictures at one-week-old how the ossicones are beginning to take shape. One-week-old ossicones, the profile v...