While the ocean may seem like a vast blue expanse, it is home to a diverse array of marine life in many colors, including pink. Pink animals in the ocean span multiple species and families, from tiny coral polyps to huge whales. The pink or reddish hue comes from pigments within the animals’ bodies. Though rare compared to blues, greens, and browns, the appearance of pink serves various purposes across the animal kingdom.
Why Are Some Ocean Animals Pink?
There are a few reasons why certain ocean creatures evolved to be pink or reddish in coloration:
– Camouflage – In some environments, being pink allows an animal to blend in better and avoid predators. Corals, shrimp, and some fish species use their pinkish tones to disguise themselves against the colors of reefs and rocks.
– Warning Coloration – Vibrant pinks and reds can signal toxicity or bad taste. This warning coloration protects animals like nudibranchs by advertising their unpalatability. Predators learn to avoid pink prey species.
– Display – During mating rituals, male seabirds and mollusks may turn more pink. By becoming more colorful, they attract females and compete for mates. Their temporary pinkness signals health and fitness.
– Blood Circulation – In vertebrates like some whales and dolphins, pinkish skin occurs from increased blood flow to surface capillaries. Greater blood circulation can help with temperature regulation. It also results in visible skin reddening.
– Pigment Production – Unique pigments are responsible for many pink animals. Corals and shellfish like shrimp get pink from carotenoid pigments they ingest in their diet or that live in their tissues. Other pigments like pteridine and papiliochrome can also appear reddish.
Examples of Pink Ocean Animals
Many unusual marine creatures display some level of pinkness. Here are several examples:
Pink Sea Star
One iconic pink invertebrate is the pink sea star, also known as the ochre sea star or starfish. These five-armed echinoderms have a bright pink tone thanks to carotenoid pigments concentrated in their skin and tube feet. They feed on mussels and clams along the Pacific coast.
Caribbean Spiny Lobster
When young, Caribbean spiny lobsters are transparent with some speckled pink coloring from carotenoids acquired through their diet. As adults, they turn reddish overall and develop their distinctive spiny antennae. These nocturnal crustaceans stay hidden in crevices by day.
Flamingo Tongue Snail
This gastropod mollusk resides in the Indo-Pacific region. Its shell is creamy-white, but its soft body ranges from orange to bright pink due to high levels of carotenoids. Its vivid pink foot gives it the common name flamingo tongue. The snail feeds on sponges and other small invertebrates.
Pink Anemone
Sea anemones like the beaded sea anemone and strawberry anemone display vivid pink tentacles. These polyps obtain pink and purple pigments called anthozoans from symbiotic algae that live within their tissues. The tentacles contain stinging cells used to capture passing fish and plankton.
Roseate Spoonbill
With feathers of light pink, this unusual wading bird inhabits saltwater coasts and wetlands. Its pink comes from carotenoid pigments obtained through a diet of shrimp and other small pink crustaceans. It sweeps its flattened bill side-to-side when feeding in shallow water.
Marine Mammal Examples
While less common, some dolphins, whales, and porpoises also demonstrate various shades of pinkness:
Amazon River Dolphin
The Amazon river dolphin has a distinctive pink coloration. As adults, they range from light pink to bright pinkish-red. Their skin contains blood vessels very close to the surface, giving them an overall pinkish tint. These freshwater dolphins are found throughout the Amazon and Orinoco river basins.
Pink Dolphin
Unrelated to river dolphins, the pink dolphin is a species of oceanic dolphin found around Hong Kong and Taiwan. Their pinkness also results from extensive blood capillaries near the skin surface. Pink dolphins feed on various fish and squid species. They are listed as vulnerable to extinction.
Dusky Dolphin
Dusky dolphins develop light pink markings as adults. They have a dark gray body with a pale pink belly, pink eyepatch, and longitudinal pink stripe. Their pinkness likely helps with thermoregulation in cool waters and communication within groups. They are highly acrobatic and social dolphins.
Beluga Whale
While white as adults, baby beluga whales or calves have a pale pink hue. This is because their skin is thinner and more transparent when young, revealing underlying blood vessels. The pink coloration quickly fades as the calves mature. Belugas inhabit cold Arctic and subarctic waters.
Flamingos and Krill
One key source of pinkness in the marine ecosystem is krill, tiny pinkish crustaceans abundant in southern oceans. Krill feed on algae and get carotenoids that help turn them pinkish-red. Krill are eaten by flamingos, shrimp, lobsters, fish, and whales, passing the pigments up the food chain.
Unique Pink Corals
Several species of colorful coral display hues of pink:
Pink Clove Coral
This coral has round, foot-wide heads covered in chunky, bubblegum-pink polyps. It grows in shallow reef environments with good water flow. The pink clove coral gets its bright color from its zooxanthellae symbiotic algae and high densities of pink chromoprotein pigments.
Carnation Coral
With a delicate, branching structure, this coral features polyps of soft pink, red, or greenish hues. It often has striking striations of contrasting color. Carnation corals contain specialized fluorescent proteins that help generate their pinks and reds. They help form underwater coral gardens.
Sunset Cup Coral
The sunset cup coral lives up to its name with brilliant pinkish-orange colors. Its dominant pigment is likely a novel chromoprotein called kolumbin. Vibrant polyps extend from stony coral structures. The coral glows under blue light thanks to fluorescent protein complements.
Tubipora Musica
Also called organ pipe coral, this species hosts symbiotic algae that provide a range of pinks, purples, and reds. Polyps emerge from parallel vertical tubes, resembling organ pipes. Tubipora musica requires strong light and water flow and is susceptible to bleaching. Vibrant colonies are indicators of reef health.
Pink-mouthed Reef Fish
Reef fish like parrotfish, wrasses, and surgeonfish often display pink mouths or pink body markings. Their diets, rich in algae, zooplankton, or coral polyps containing carotenoids, lead to pinkish hues in their mouth tissues and body pigmentation. Examples include the pinktail wrasse, pinkstreaked wrasse, and McCosker’s wrasse.
Conclusion
While the deep blue ocean appears dominated by cooler colors, a diversity of pink and reddish marine creatures exist. Ranging from tiny shrimp to giant whales, scattered populations of pink animals occur thanks to specialized pigments, circulatory adaptations, diet, camouflage needs, mating displays, and symbioses with colorful algae. Unique pink corals and reef fish also rely on pigments acquired through their coral and algal food sources. The natural pinkness of krill even colors flamingos on shore. So while it represents a small fraction of all ocean life, the presence of pink marine animals illustrates the awe-inspiring diversity, adaptability, and interconnectedness of species within the global ocean ecosystem.
