You Are (in some species, the color of) What You Eat
Sunday
Newborn flamingos have grey feathers, but become pink by eating brine shrimp. These shrimp are full of carotenoids, which the shrimp in turn get from the tiny algae they eat. Flamingos break down these carotenoids in their liver and deposit the compounds as orange and pink pigment throughout the bird’s body.
Monday
Salmon flesh also gets that salmon color from the tiny algae-eating crustaceans in their diet.
Tuesday
Those fishy carotenoids don’t just make things orangey-pink, though. The strikingly blue (and large) feet of the blue-footed booby also comes from these compounds in the bird’s seafood diet.
Wednesday
Nudibranchs, a type of sea slug, move slowly and spend a lot of time on top of what they’re eating, often sponges, algae, coral, and bright anemones, so incorporating the color of their prey into the nudibranchs’ bodies helps camouflage them while eating.
Thursday
Cedar waxwings are songbirds with naturally yellow tail tips, but the red berries of the Morrow’s honeysuckle bush, which the birds love, turns their tails orange.
Friday
The striking neck “cape” of the frill-necked lizard picks up colors from the food the reptile eats, which generally includes insects, smaller reptiles and mammals.
Saturday
The brilliant yellow of the mature male American goldfinch is also obtained from pigments in his seedy, plant-y diet.