Well, hardcore vegan’s and veggies will know this already but around a quarter of refined sugar in the US is made that way by using Bone Char; which is essentially charred animal bones that are ground into a fine powder and used in a similar way to carbon based compounds that you find in water filters and aquarium filters. <<Read the science on Wikipedia>> 

Of particular interest was that in the late 19th Century people were selling mass quantities of Buffalo bones to industry for this purpose. When they ran out of Buffalo bones some bone smugglers were digging up indian burial grounds, which I suppose now that I think about how Native American’s always prided themselves on using all the animal when they had to hunt makes an interesting moral conundrum. Either way it’s just another creepy thought to make you put down the donut and get to the gym.