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Many animals can consider themselves fortunate that their species doesn’t have to answer to an ethics committee. These creatures employ some incredibly odd, clever, and at times even ruthless 'battle tactics' to capture their prey.
10. The Sea Star’s Stomach Extension Strategy
Sea stars—formerly known as starfish—cannot see their prey, but they possess the ability to sense and follow the chemical trails left behind. When a sea star detects a clam, it utilizes the hundreds of suction-cup-like tube feet on the back of its arms to locate the clam and crawl onto its closed shell. The sea star then maneuvers the clam until the slight gap between the two shells aligns with its mouth. This gap is incredibly narrow—around 0.65 centimeters (0.25 inches)—but never fully sealed.
Next, through a strange action called eversion, the sea star extends its soft, jelly-like cardiac stomach from its mouth. It presses this stomach into the crack between the clam's shells, allowing it to slowly seep inside and release digestive juices. This process weakens the clam, enabling the sea star's tube feet to pry the shells apart.
The rest of the sea star’s stomach then enters the clam's shell, and its digestive enzymes dissolve the clam’s body into a liquid-like consistency. This process is essential because the sea star lacks teeth or claws to break the meat into smaller pieces. After the soupy meal is absorbed into its inner pyloric stomach, the sea star pulls its cardiac stomach back into its body. Any leftover shell fragments or indigestible parts are expelled through its mouth.
In recent studies, Japanese scientists found that even when mussel shells are wired shut, sea stars can still maneuver their stomachs inside and consume all the meat before the wires are even removed.
9. The Moray Eel’s Alien-Like Jaw Strategy
While most fish feed by sucking in water and food through their mouths, or by using their jaws to grab food and suction it down their esophagus, moray eels take a different approach—one that makes them seem like something from the movie Alien.
First, the moray eel latches onto its prey with its sharp outer jaws. Then, it uses a second set of jaws, known as pharyngeal jaws, located in its throat, to pull the prey closer, swallow it whole, and finish the entire process in less than a second.
Eels resemble snakes in that they must consume large prey through their narrow mouths, then push the prey down their long, slender bodies. While other eels can feed by suction, researchers believe moray eels evolved this remarkable second set of jaws because they hunt in spaces too small for their heads to expand and create suction.
8. The Crocodile’s Bait-and-Switch Tactic
For a long time, crocodiles were considered sluggish and dull creatures in the animal kingdom. However, it turns out that these reptiles are far more intelligent than anyone realized. In India, researchers observed crocodiles lying motionless in the shallow waters of a pond, with small twigs or sticks balanced on their snouts. They remained still for hours, but they weren’t being lazy; they were lying in wait, using the branches as bait to attract small birds searching for nest-building materials. The unsuspecting birds swooped in to grab the twigs, and the crocodiles struck quickly, devouring the birds alive.
Despite their tough exteriors, crocodiles are surprisingly sensitive to touch through small, pigmented domes scattered across their bodies. These sensors allow them to detect vibrations and pressure more accurately than humans can with their fingertips. The nerves within these domes are finely tuned to sense even the smallest ripples in the water, helping crocodiles pinpoint the precise location of their prey for a lethal strike. The most sensitive sensors are located near their teeth, which scientists believe helps crocodiles identify the type of prey they've captured.
7. The Humpback Whale’s Deadly Bubble Strategy
Without teeth, humpback whales rely on baleen plates—made of keratin with bristle-like edges hanging from their upper jaw—to filter large amounts of herrings, krill, and other small prey for nourishment.
Additionally, humpback whales are the only baleen whales known to feed cooperatively, using bubble nets to trap their prey. They work together in teams, or pods, typically consisting of five to eight whales. While bubble net techniques can vary by region and individual whales, they generally serve as a strategy for the pod to capture more prey than any single whale could on its own. Occasionally, one pod will even steal another's bubble net.
Taking Southeast Alaskan humpback whales as an example, the hunt begins when a pod dives below a school of herring. The humpbacks then emit feeding calls to drive the panicked herring upwards into a tight cluster. The more self-preserving herring tend to hide in the center of the group, ironically making them even more vulnerable to capture.
As the herring rush toward the surface, the humpbacks release streams of air bubbles from their blowholes, surrounding the fish in a bubble net. Since herring won’t swim through the bubbles, their horizontal escape is blocked. However, if individual fish become separated from the school, they might slip through the bubble barrier and escape (which makes hiding in the center of the school such a poor strategy). Once the herring are trapped, the humpbacks swim upward through the net with open mouths, and the fish are caught.
6. The Squid’s Club, Flap, and Flutter Tactic
The typical squid possesses eight arms and two tentacles. The tentacles are longer than the arms and have tips, known as clubs, which are equipped with hooks or suckers. The squid shoots its tentacles forward, ensnares its prey with the clubs, and then pulls the prey toward its mouth.
However, there is one particular deep-sea squid—Grimalditeuthis bonplandi—that employs a unique battle tactic. In a sense, it has no other option. The G. bonplandi is too slow and weak to capture prey in the same manner as the typical squid. Its tentacles also lack hooks, suckers, and photophores (the glowing spots that attract food).
Around a mile beneath the ocean’s surface, the G. bonplandi remains motionless, with its arms spread out in the water and its long tentacles hanging down. The squid’s tentacles don’t move independently but instead have fin-like membranes on their clubs that flap, flutter, and seemingly swim off like tiny creatures. The tentacles trail behind, but even when fully extended, the clubs continue to swim on their own.
Due to the extreme depth and darkness of its habitat, researchers have never directly witnessed the G. bonplandi feeding on prey. However, they hypothesize that the swimming motion of the squid’s clubs draws in shrimp and smaller squids. Lacking glowing spots, these clubs remain invisible, and when prey ventures too close, the squid may use its arms to ensnare them.
Another possibility is that the flapping clubs attract prey by disturbing glowing microscopic organisms, creating a vibrant glow in the water. Alternatively, some researchers believe that the vibrations and movement produced by the clubs might deceive prey into thinking that either their companions are signaling them or that the movements are caused by other prey.
5. The Japanese Sea Catfish’s pH Detection Strategy
The nocturnal Japanese sea catfish inhabits waters around the southern tip of Japan and the Ryukyu Islands. John Caprio, a researcher from Louisiana State University, discovered that sensory nerve fibers on the catfish’s whiskers (or barbells) are sensitive to slight changes in the pH (acidity) of seawater. These sensors enable the Japanese sea catfish to find its prey—small sea worms known as polychaetes.
Polychaetes reside in tiny mud tunnels on the ocean floor. As these worms breathe, they release small amounts of carbon dioxide, which interacts with the seawater to form carbonic acid, resulting in a minor pH drop of about 0.1 around the entrance to the worm’s burrow. When the catfish senses this shift, it dives down and inhales the worms from their hiding places. As Caprio puts it, “These fish are like swimming pH meters. They are just as accurate as a commercial pH meter in the lab.”
The catfish’s sensory fibers are most responsive at the natural seawater pH of 8.2. However, when the pH drops to 8 or lower, the catfish significantly loses its ability to locate food. Scientists are concerned that the ocean’s acidification due to global warming may impair this animal’s hunting skills and its ability to capture prey.
4. The Comb Jellies’ Stealthy Submarine Tactic
Comb jellies, often mistaken for jellyfish, aren’t actually jellyfish. They are slender, transparent invertebrates from the phylum Ctenophora. Their name comes from the comb-like ridges running along their bodies, which contain thousands of cilia that act like tiny propellers. These cilia help propel the jellies through the water while also generating a current that pulls in food. Their movements create a stunning flashing rainbow effect as light refracts off the cilia.
Comb jellies don’t have a brain or specialized sensory organs, just a simple nerve net that detects chemical signals from their prey in the water. One species, the North American comb jelly, is a ravenous feeder, consuming large amounts of zooplankton. Though sightless and unaware of the rainbow light show, some of their prey—such as copepod plankton—are highly sensitive to even the slightest water disturbances.
To catch these alert copepods, the comb jellies adopt a stealthy submarine approach. They move at an incredibly slow pace to avoid detection, ensuring they don’t create any turbulence in the water. When they open their mouths, the unaware zooplankton swim right in. By the time the prey realizes its mistake, it’s too late to escape.
3. The Lionfish’s Terminator Tactic
Most predatory fish prefer hunting in large groups of prey, as it requires less energy to catch them. When the prey population decreases, these predators typically move on to other areas with more food. However, lionfish are different—they act more like the Terminator, choosing to remain in one area until their prey is locally extinct.
Lionfish, native to the Pacific Ocean, are stunningly colorful with large, spiny fins. Their vibrant hues are not just for show; the sharp, venomous spines keep them safe from other marine creatures. Since the late 1980s, when hobbyists and local aquariums are believed to have introduced them to the waters off Florida, lionfish have thrived in the Atlantic and parts of the Caribbean. The native fish in these areas, unaware of the lionfish’s danger, are easily outwitted. By fanning their fins, lionfish corner their smaller prey and launch a swift, surprise attack to swallow them whole.
In some regions of the Atlantic, lionfish have wiped out over 90 percent of the native fish population. To combat this ecological threat, scientists have been removing large numbers of lionfish from certain reefs to create sanctuaries where native fish can repopulate. In areas where lionfish numbers have been reduced by 75–95 percent, native fish populations have rebounded by 50–70 percent. This is promising news, as eradicating lionfish from these regions completely is now nearly impossible.
2. The Swordfish’s Scorching Eyes Strategy
Swordfish, like other large, powerful marine predators, are cold-blooded except for their eyes, which they actively heat. This helps them maintain superior vision to track fast-moving prey, such as squids, by giving their eyes a warmer temperature than the rest of their body.
To achieve this, swordfish have evolved a special muscle—originally responsible for moving their eyes—that now functions as a heating organ. This adaptation allows them to raise the temperature of their roughly tennis-ball-sized eyes by 10–15 degrees Celsius (50–60 °F) above the surrounding water. In controlled studies, swordfish eyes heated to 20 degrees Celsius (68 °F) could capture light over 10 times faster than those at the surrounding ocean temperature, which averages about 3 degrees Celsius (37 °F) at the greatest depths.
This visual processing resembles a camera with a rapid shutter speed. Instead of seeing a blurry image, the swordfish perceives its fast-moving prey more sharply in the cold, murky, yet still well-lit depths of the ocean, often 300–500 meters (1000–1650 ft) below. Squid and other prey cannot detect its approach because, unlike the swordfish, they are unable to warm their eyes, making it hard for them to see clearly.
1. The Ground Beetle’s “Make My Day” Strategy
Typically, frogs feast on insects. However, ground beetles from the genus Epomis don’t follow this pattern. Instead, they lure their potential predators into a trap, turning them into a meal—and they succeed almost every time.
In this role reversal, the beetle carefully maneuvers its mouthparts and antennae to grab the attention of toads, frogs, and other amphibians. It's like Clint Eastwood daring them with, “Go ahead. Make my day.” When the frog attacks, the beetle skillfully dodges the tongue and uses its double-hooked mouthparts to latch on. It then begins to extract fluids while feeding on the frog's body. In nearly all cases, the Epomis ends up killing the larger amphibian and enjoying a tasty feast as a result.
