If you’ve ever been fishing and captured an unfamiliar fish, you might be afraid at first to grab it by the mouth, and for good reason; it’s no secret that fish can have some ferocious teeth! The mind immediately goes to colossal Great White and Tiger Sharks shredding apart their prey with massive sharp teeth, but many lesser-known yet still magnificent members of the fish world have an incredibly impressive and diverse array of teeth. It’s not just the physical structure of teeth that is so impressive, but also the way that fish capture and consume their prey. From little Archer fish that shoot droplets of water at insects resting on branches just above the water’s surface to giant Goliath Groupers engulfing unsuspecting stingrays whole, the different ways in which fish obtain their food is nothing short of captivating.
Take the Red-Bellied Piranha, for example. Native to South America, these fish attack their prey in schools, using razor-sharp teeth and rapid head shakes to shred their meals into bite size pieces. Fans of the TV show River Monsters may remember another startling fish from the Amazon: the Payara. Equipped with huge sharp fang-like teeth, the Payara snaps up and punctures its prey; rightfully earning the nickname “vampire fish”.
However, it’s not just sharp teeth that fascinate fish enthusiasts. Other fish exhibit teeth that boggle the minds of curious anglers due to their unusual nature. The Sheepshead, for example, is famous for its teeth that appear nearly identical to the teeth of a human. They use these molar-like teeth and incredibly strong jaws to crush their prey of clams, mussels, crustaceans and even barnacles. Many fish that people are more familiar with, however, simply have small sandpaper-like teeth designed to grab and hold prey; such as one of North America’s most popular sportfish: the Largemouth Bass. The diversity of tooth shape and structure as well as feeding behavior warrants research that allows scientists to better understand the biology and feeding behavior of fishes.
Most scientific studies up to this point have focused explicitly on assessing morphological traits of fish and their teeth to infer how they capture and consume their prey. However, in this new paper, Pooventhran Muruga and colleagues at James Cook University develop a novel method of studying how the structure of fish teeth and feeding behavior impact damage inflicted to prey. Building on techniques used in forensic odontology (the study of evaluating dental evidence from criminal cases), researchers assessed the bite wounds inflicted on prey items. Twelve species of piscivorous fish (fish that eat primarily other fish) were analyzed. The selected piscivores included fish with and without modified pharyngeal jaws (jaws with teeth) and those from two functional groups: grabbers and engulfers. The difference being that grabbers have small pointy teeth and quickly grab and shake their prey to inflict damage, whereas engulfers have large relatively blunt tooth patches and tend to swallow their prey whole.
To assess bite wounds, fish prey were fed to each predator fish in an aquarium and the prey item was quickly removed from the predator’s stomach to assess any damage. Researchers assessed damage to prey by photographing the wounds and used an image processing software to quantify the area exhibiting damage from four distinct categories: superficial, incision, laceration, and missing flesh. After analyzing damage inflicted to the fish prey, Muruga and colleagues found that engulfers rely on their speed and protruding jaws to capture prey whole and head first, inflicting minimal damage to their prey. Prey consumed by grabbers, on the other hand, were often captured tail-first, shaken to inflict damage, and then spit out and swallowed head-first; resulting in a greater likelihood of damage in all four categories. Predators with modified pharyngeal jaws also inflicted much more damage to their prey than predators without.
The novel method of assessing fish bite damage developed in this study provides the framework for future studies to learn more about how fish capture and wound their prey for consumption, which will provide us with insight into a component of fish biology that has been difficult to study until now. Perhaps we will be able to eventually learn even more about how some of the most unusual toothy aquatic predators capture and damage their prey before making a meal of them!
Zach Crum is from Chesapeake, Virginia and received his Bachelor’s of Science in fish conservation from Virginia Tech. He is currently a Master’s student in the Bressman Lab at Salisbury University where he studies the feeding ecology of invasive fishes on the Eastern Shore of the Chesapeake Bay. Zach is an avid angler and is passionate about fish ecology, biology, and conservation. He can be reached at firstname.lastname@example.org