Which Came First, Predator or Prey?

Very few food web interactions occur like Wile E. Coyote and the Road Runner. The ocean doesn’t surprise drop anvils on predators to prevent them from capturing prey. A caught meal means longer survival, not just the end of a cartoon chase sequence. However both Wile E. Coyote and Road Runner demonstrate specific adaptations to aid in survival. Wile E. Coyote shows cunning and planning in his hunting strategy, Road Runner is built for speed to avoid such traps.  These characteristics often evolve together over time, an increase in fitness of one leading to an increase in fitness of the other.  Here we’ll look at a few specific chondrichthyes and how they’re adapted to be predator, prey, and sometimes both!

New Atlas

The deep sea Goblin Shark is an ambush predator, slowly swimming near its prey, and then BAM extending out its intense jaws nearly three inches to capture a meal.  Surprising fast prey can decrease the time available to swim away. The Goblin Shark’s long snout is covered in ampullae of lorenzi, special electroreceptors which aid in finding camouflaged prey in dark, murky environments. As prey species develop colorations fit for blending in, other species have evolved strategies to discover hidden food. Goblin sharks also have different types of teeth, some acting as daggers for spearing fish and others acting like grinders to crunch prey that have developed tougher outer skin for protection. Even though some predators specialize in hunting one type of prey, goblin sharks are adapted to catch many different critters. Not being picky can help a predator survive if something negative (pollution, overfishing, etc.) happens to their prey population. 

In shallower waters we can find various benthic feeders well adapted for their environment on the bottom of the ocean floor.  The underside mouth placement and grinding teeth of many skate and ray species help them find and crunch prey (mostly mollusks and crustaceans that have adapted to life hidden in the sand). A specific ray, the Clearnose Skate camouflages to avoid being eaten by larger sharks and fish. Unlike stingrays, skates don’t possess a spine, but rely on thorns for extra protection. As predator and prey, the Clearnose Skate survives by camouflaging into its hunting grounds.

Next up we have an extremely intriguing filter feeder, the Basking Shark.  Even though they have teeth, they used specialized gill rakers to clean out their tiny prey, plankton. The large mouths of a basking shark can filter 2,000 tons of seawater in 1 hour, which is optimal when feeding on small food. Other shark species also  filter feed (Whale Shark and Megamouth Shark), but the Basking Shark doesn’t suction water in. It relies on swimming with its mouth open; similar to if you swam through soda with your mouth open instead of sucking it up through a reusable metal straw. While basking shark’s large size and tough skin keep them from ending up as prey items, plankton are very susceptible to pollution. Plankton form the base of many food webs, and even if we can’t see the die off of these small plants and animals, we’ll notice their missing link in the collapse of our ocean food webs. 

marlin.ac.uk

Why does the ocean need both predators and prey? Can’t we all get along and eat rainbow cakes? In a system even more complex than (dare I say it?) high school, balance is key. The populations of predators and prey can even affect animals below/above/across from them in the food chain. The removal of an apex predator could even affect the plant life of the habitat, not just the animals. Without understanding the detailed interaction we could unknowingly remove a keystone species. This is extremely important for humans because we use many parts of the ocean as a resource. If we focus on one level and disregard the impact on others, we could prevent ocean resources from being used by future generations for food, water, or even the progression of knowledge.  Many chondrichthyes display jaw-some adaptations found nowhere else, and everyone deserves a chance to learn about them!

glossary

• Predator: an organism that exists by eating other organisms
• Prey: an organism that gets eaten by other organisms
• Adaptation: a characteristic or behavior that helps an organism survive
• Evolve: change over time
• Fitness:  the ability of a population to maintain or increase population size over generations
• Ambush Predator: an animal that catches its prey by stealth, speed, and/or surprise
• Ampullae of Lorenzinni: any of an array of electroreceptors in the head of sharks, skates, and rays capable of detecting weak electrical signals produced by muscular activity in other creatures.
• Camouflage: blending in or hiding in a natural environment
• Benthic: of or relating to the bottom
• Filter Feeder: an aquatic animal that feeds on particles or small organisms strained out of water by circulating them through its system
• Gill Rakers: structures that prevent food from escaping through or damaging the gills
• Plankton: microscopic plants and animals
• Apex Predator: an animal at the top of a food chain or web
• Habitat: the area an animal lives in, including food, water, shelter, and space
• Keystone species: an organism that if removed from its ecosystem, the system would change drastically

GUEST BLOGGER AND TFUI OFFICER CARISSA THIEL

Carissa Thiel graduated with a BS in marine biology and then spent a few years working in environmental education. She now works as a Guest Engagement Educator, spreading conservation messages to locals and visitors alike!

Carissa loves exploring, reading, talking to people, and awkward get to know you questions. If she could be any bird she would want to be an osprey, because they have wonderful adaptations to hunt fish and are always found by water. However, she would probably be an emu because they have long legs, make awkward faces, and only watch other birds fly.