What make blood oranges red
The coloring of a blood orange differs from a typical orange because it has an additional pigment called anthocyanin.
Yes, some red fleshed oranges taste different than others. What we think of as "blood orange" is the tarrocho (originally from Sicily) which has notes of rasberry in the flavor. Cara cara on the other hand lack that.
Cara cara also lacks acidity and taste! I was so disappointed when I bought a bag of them. Never again!