Sharks have a strong sense of smell and taste that helps them detect prey in the ocean. Their preferences and aversions to certain tastes and smells is not well understood but some insights can be gained by examining shark anatomy and behavior.
Shark Taste Buds
Sharks have taste buds located in their mouths, throats, and sometimes on their fins. The density and distribution of taste buds varies by shark species. In general, shark taste buds are clustered in the areas around the teeth and jaws where food is manipulated and consumed. They have preferences for certain amino acids like glycine, creatine, and betaine that correspond to high protein foods like fish and squid. Sharks tend to avoid bitter, sour, or acidic tastes which may signal toxicity or spoilage. Their powerful sense of smell also informs taste preferences.
Common Shark Prey
Most sharks are opportunistic predators that feed on a wide variety of prey. However, common food sources provide some clues about flavors and textures sharks seek out:
- Small fish like sardines, mackerel, and herring
- Squid, octopus, and cuttlefish
- Crustaceans like shrimp, crabs, and lobster
- Small sharks and rays
- Marine mammals like seals, sea lions, dolphins, and whale carcasses
- Sea turtles
- Seabirds
These prey items are high in protein, fatty acids, and other nutrients sharks need. The flesh tends to be soft and easy to bite and swallow. Sharks often ambush and pursue these prey species, indicating a preference for their taste and texture.
Foods Sharks Avoid
There are certain food items sharks tend to avoid or spit out after tasting. These provide clues about flavors they may find unpleasant:
- Pufferfish and porcupine fish – contain tetrodotoxin poison
- Hairy animals like sea urchins – difficult to swallow
- Hard-shelled organisms like clams, mussels, oysters – difficult to crush and swallow
- Plant matter like seaweed and algae – low nutritional value
- Rotten, spoiled, or carrion with high bacteria loads – increased risk of illness
- Potentially toxic species like lionfish, soapfish, stingrays
Sharks often reject or spit out these items after mouthing or biting them. The taste, texture, low nutritional value, or potential toxicity likely deters them.
Taste Deterrents
Certain artificial and natural compounds have been tested to see if they act as taste deterrents for sharks. Some that induce avoidance behavior or reactions in sharks include:
- Cadmium chloride – artificial compound, registered shark repellent
- Rotten shark flesh – signals contamination/toxicity
- Bitter tastes – quinine, citrus extracts
- Sour and acidic tastes – vinegar, lemon/lime juice
- Pungent spicy flavors – chili peppers, ginger, horseradish
- Eucalyptol and eucalyptus extracts – naturally occurring repellent
These tastes likely signal toxicity or spoilage and cause sharks to reject potential food items. The strong odors and flavors over-stimulate the shark’s sensitive receptors. Caution should be taken though, as some deterrents may attract sharks out of curiosity.
Tastes Sharks Enjoy
Sharks are attracted to certain artificial and natural bait flavors. Savory umami flavors like glycine and betaine signal protein-rich foods. Sharks also seek out these tempting tastes:
- Fish oils and fatty acids
- Amino acids from blood and tissue
- Ammonium compounds like urea and trimethylamine
- Sodium and potassium salts
- Nucleotides like ATP, IMP, and AMP
- Organic acids like citric, lactic, and succinic acid
Foods containing these compounds grab the attention of sharks and induce a strong feeding response. Sharks can detect minute quantities in the water from great distances. Using these attractants is an effective fishing and baiting technique.
Taste Preferences by Species
Different shark species have specialized diets and preferences for certain prey. Their taste receptors and behaviors have adapted to target accessible food sources:
| Shark | Preferred Prey | Flavor/Taste Preferences |
|---|---|---|
| Great white shark | Marine mammals like seals, fish, seabirds | Fatty acids, protein, blood, umami |
| Tiger shark | Sea turtles, fish, seabirds, mollusks | Umami, amino acids, glycine |
| Bull shark | Small fish, crustaceans, mollusks | Amino acids, nucleotides, glycine |
| Hammerhead shark | Stingrays, octopus, crustaceans, small fish | Nucleotides, amino acids, ammonium |
| Mako shark | Fast-moving fish like tuna, mackerel, swordfish | Blood, protein, amino acids |
Their specialized diets demonstrate taste preferences for specific compounds found in their prey items.
Taste Adaptations in Sharks
Sharks have evolved anatomical and physiological adaptations to enhance their sense of taste and ability to detect chemical stimuli in the water:
- Taste buds – Concentrated on lips, mouth cavity, pharynx, and head.
- Olfactory organs – Paired olfactory bulbs connect to nostrils to smell prey.
- Lateral line – Sensory canal along body detects water movements.
- Ampullae of Lorenzini – Jelly-filled electroreceptive pores detect electric fields of prey.
- Powerful jaws – Allow sharks to bite and sample novel objects.
This gives sharks an augmented sense of taste and ability to detect chemical stimuli diluted in the water at low thresholds. They can use taste and chemoreception to identify and locate favorable prey from great distances.
Conclusion
In conclusion, sharks have specialized taste preferences shaped by their evolutionary history as aquatic predators. They use their powerful sense of taste and smell to locate nutrient-rich foods like fish, seabirds, and marine mammals. Compounds like amino acids, nucleotides, and fatty acids stimulate strong feeding behavior. However, sharks avoid bitter, acidic, and sour compounds that may signal toxicity or spoilage. Their taste adaptations allow them to sample their environment and selectively pursue favorable prey while avoiding dangerous or low-value foods. While much is still unknown about sharks’ sense of taste, it is clear they can discern different chemicals and textures that influence their foraging choices in the ocean.