Yuck! There’s such a thing? With real blood???
No. It’s just a variety of orange.
On the outside, they look like a regular orange, maybe a little darker. But the flesh is deep, blood red. The juice will stain your fingers red. They are delicious.
Blood orange is just a names. It’s basically an orange with red and mixed flesh, instead of just orange flesh. They have have a stronger, sometimes berry-like flavor. Cara Cara oranges are kind of pinkish flesh.
From Wiki:
Blood orange
The blood orange is a variety of orange (Citrus sinensis) with crimson, blood-colored flesh. The fruit is smaller than an average orange; its skin is usually pitted, but can be smooth. The distinctive dark flesh color is due to the presence of anthocyanins, a family of pigments common to many flowers and fruit, but uncommon in citrus fruits.[1] Sometimes there is dark coloring on the exterior of the rind as well, depending on the variety of blood orange. The degree of coloration depends on light, temperature and variety.
The blood orange is often described as a hybrid between the pomelo and the tangerine, but it is actually just a mutation of a sweet orange.[2]