The ocean is filled with strange and wonderful creatures, some that may not appear to be what they seem at first glance. One of the most fascinating examples are fish that closely resemble lizards in appearance and behavior.
These incredible fish have evolved lizard-like traits as a form of mimicry to help them survive and thrive in their environments.
If you’re short on time, here’s a quick answer to your question: There are several species of fish, like the Indonesia-based mimic surgeonfish and the Caribbean trumpetfish, that have evolved to closely imitate the appearance and movements of land-based lizards as a defense mechanism against predators.
Background on Mimicry in Fish
Definition and purpose of mimicry
Mimicry is a survival strategy used by many animals, including fish, where one species evolves to resemble another species. The purpose of mimicry is to gain protection, avoid predation, or improve ability to find food.
By mimicking the physical appearance and behaviors of another species, the mimicking species hopes to “trick” predators or prey into mistaking them for something they are not.
There are several types of mimicry observed in the fish world. Common examples include:
Common types of mimicry used by fish
- Batesian mimicry – a harmless species resembles a dangerous or toxic species, like a triggerfish resembling a boxfish.
- Mullerian mimicry – two harmful species resemble each other, like multiple species of lionfish.
- Aggressive mimicry – a predator resembles a harmless species, like the alligator pipefish mimicking a reef cleaner fish.
The specific type of mimicry depends on whether the model species being mimicked is harmful/toxic or harmless. In all cases, the mimic gains safety, access to prey, or freedom from predation that its true appearance would not afford it.
Benefits of mimicking lizards specifically
Some fish species, like blennies and snakeheads, have evolved amazing mimicry of land animals like lizards. By resembling the body shape, patterns, and even behaviors of land species, these fish enjoy unique benefits including:
- Avoiding predators – Many aquatic predators prefer to avoid anything resembling a land animal or may mistake the mimic for an actual lizard/snake.
- Accessing prey – Mimicking land animals may allow access to unique food sources such as insects or amphibians.
- Territory defense – Appearing like a fierce lizard helps scare away competing fish species.
Researchers have discovered some incredibly clever cases of lizard mimicry in fish species around the world. For example, the sand lance Lethops connectens mimics the red-headed rock agama lizard in Egypt, while the blenny Meiacanthus anema mimics chameleons in Indonesia with swaying head movements and ability to change color!(1) This diversity of mimicry adaptations shows the strong selective advantage gained by fish able to resemble land-dwelling reptiles.
Fish Species That Mimic Lizards
Mimic surgeonfish
The mimic surgeonfish (Acanthurus chronixis) is a species of tropical fish found in the Indo-Pacific oceans. As their name suggests, these small fish have evolved to closely resemble certain venomous species of sea snakes.
By mimicking the color patterns and movements of sea snakes, the surgeonfish gain protection from predators who want to avoid a nasty snake bite. These clever fish feature black bands and splotches over a whitish-blue body, complete with a narrow head and tail to complete the serpentine illusion.
Though not venomous themselves, if threatened the surgeonfish will erect their pectoral fins to further imitate the cobra-like hood seen on sea snakes. This form of mimicry is called Batesian mimicry.
Some key facts about mimic surgeonfish:
- They grow up to 13 inches (33 cm) long.
- Found in coral reefs of the Indo-Pacific at depths of 10-131 feet (3-40 m).
- Herbivorous; diet consists mainly of algae.
- Lifespan around 9 years in the wild.
By mimicking the appearance of the deadly but placid sea snake, the surgeonfish reminds predators like groupers, sharks and eels that it’s better to avoid these patterns altogether rather than risk being bitten.
This self-preserving trick allows the surgeonfish to swim through the reef with relatively little concern for predators.
Trumpetfish
The trumpetfish (Aulostomus maculatus) is another lizard impersonator that swims among coral reefs in the tropical Atlantic, Pacific and Indian Oceans. Growing over 3 feet (1 m) long, these elongated fish perfectly mimic the shape of a small sea snake or eel.
Their compressed bodies are usually tan to brown, with vertical bands and spots that reinforce the serpentine resemblance. Using tiny fins for propulsion, trumpetfish swim in a sinuous, lizard-like fashion to complete the ruse. This can fool predators and prey alike!
Fun facts about the trumpetfish:
- They have excellent camouflage to blend with corals.
- Ambush predators that suck in smaller fish in 0.6 seconds!
- Use their long snouts to probe crevices and blow jets of water to expose hidden prey.
- Masters of disguise that can change color to match their surroundings.
The trumpetfish’s imitation of sea snakes not only protects it from being eaten, but also allows it to get closer to unsuspecting prey fish. By mimicking a venomous reptile, the trumpetfish can swim right next to smaller fish without causing alarm.
With lightning speed, it then sucks its prey into its tubular mouth whole. The trumpetfish’s snake-like ruse serves it well both for defense and stealthy hunting!
Seahorses
Seahorses are a unique species of bony fish that swim upright and closely resemble tiny seahorses. These beautiful fish live in shallow tropical and temperate waters across the world. Many species have evolved incredible camouflage that allows them to mimic the color and textures of sea grasses and corals in their environment.
Several species, like the western spiny seahorse and pygmy seahorse, take camouflage further by mimicking the appendages of other marine organisms.
Here are some fascinating facts about seahorses:
- Their prehensile tails can tightly grip sea grasses and corals.
- Males get pregnant and give birth to up to 2,000 tiny seahorses.
- They are ambush predators that suck in plankton and small crustaceans.
- Some species can change color for camouflage in as little as one week.
- They perform elaborate mating dances and pair for life.
Many seahorse species can grow skin filaments and protuberances to blend in perfectly with their surroundings, whether it’s algae, sea grass or gorgonians. By rocking back and forth with the current, they can avoid detection among the living backdrop.
The seahorse’s chameleon-like talents make them exceptional lizard mimics. Their impressive camouflage allows them to ambush tiny prey and go unnoticed by predators swimming nearby.
Ghost Pipefish
Ghost pipefish live up to their name – these tropical fish species are transparent and can become almost invisible in open water. Their bodies are soft and flexible, with small dorsal and tail fins that enable them to mimic the movements of drifting sea grasses and feathers.
This allows the ghost pipefish to float along vertically while perfectly camouflaging itself as just another piece of harmless drifting debris.
Here are some interesting ghost pipefish facts:
- Related to seahorses and pipefish.
- Males brood eggs in a ventral brood pouch until hatching.
- Feathery appendages wave to resemble plants drifting in the current.
- Slowly bob up and down or sway side-to-side when threatened.
- Consume tiny crustaceans and plankton.
By imitating floating plants and impersonating the gentle sway of sea grasses, the ghost pipefish disappears before the eyes of potential predators. And unsuspecting prey rarely notice the stealthy predator lurking in open water until it’s too late!
This unique imitation helps the ghost pipefish survive in a marine habitat where there’s little to hide behind.
Leafy Seadragon
The mystical leafy seadragon (Phycodurus eques) could win an award for the most elaborate imitation of marine flora. Found along southern and western Australia, these fish are true masters of disguise. Their entire bodies are covered in leaf-like appendages attached with small stalks.
Webbed protrusions and skin flaps complete the foliage façade. The leafy seadragon sways gently just like real drifting algae plants and sea grasses. Combined with exceptional camouflage coloration, this fish is a chameleon of the sea!
Some amazing facts about the leafy seadragon:
- Grows up to 20 inches (50 cm) long.
- Masters of camouflage and mimicry.
- Males brood eggs until they hatch after about 9 weeks.
- Closely related to seahorses and pipefish.
- Classified as Near Threatened due to habitat loss.
The leafy seadragon’s magical appearance lets it disappear against backgrounds of sea grass meadows, macroalgae and reef structures. By mimicking drifting plants, it can float right next to potential prey while remaining invisible.
This Lizard of the Sea has perfected the art of impersonation and sets a new standard for marine camouflage!
Physical Adaptations That Allow Mimicry
Coloration and patterning
One of the most remarkable ways fish mimics disguise themselves is through meticulous coloration and patterning. Species like the saber-toothed blenny and the harlequin snake eel have color patterns that precisely match their models, allowing them to blend into their surroundings seamlessly.
The similarities go beyond general coloration to include minute details like eyespots, streaks, and fins that precisely match the organisms they are impersonating. Some fish can even change their coloration temporarily to match different environments or fool different predators.
This degree of morphological precision enables nearly flawless camouflage.
Body shape and fins
In addition to colors and patterns, many imposter fish closely emulate the body shape and fins of their models. The harlequin snake eel has an extremely elongated body and pointed tail that allows it to swim and move just like a sea snake.
Other eels like the snakelocks anemonefish have evolved bodies that look just like the anemones they live in. Creatures like the saber-toothed blenny have dorsal fins positioned precisely like venomous lionfish and bodies shaped like the corals they perch on.
The uncanny similarities in body form and fins between mimics and models are essential for tricking predators and allowing the imposters to hide in plain sight.
Head shape and eyes
Mimicry in fish has evolved to incorporate minute details like the shape of the head and eyes. For example, blennies impersonating lionfish position their eyes in the same position on an oversized head.
Some impersonators even have markings by their eyes to emulate the “glasses” of species like moorish idols. The head shape and eye placement need to be virtually identical between mimics and models to complete the illusion and fully deceive predators.
Eyes in particular can be a clear giveaway that something is not what it pretends to be, so the precision of mimicry related to the head is critical.
Movements and behavior
To truly impersonate other aquatic organisms, mimic fish need to act the part convincingly. Simply having the appearance of another creature will not be enough to deter predators if the behavior gives them away.
For example, blennies mimicking lionfish replicate the way lionfish slowly open their fins when threatened. Snake eels undulate their bodies like serpents to maintain their disguise while swimming. Mimicry has evolved to incorporate behavioral adaptations that make fish convincingly replicate how their models move, feed, and interact with their surroundings.
Just as coloration has to be precise, the movements and behaviors of mimics also reflect the creatures they are impersonating.
Evolutionary Explanations for Lizard Mimicry
Natural selection
Natural selection is considered one of the key drivers behind the evolution of fish that mimic lizards. This process favors genetic traits that increase an organism’s chances of survival and reproduction.
For fish that resemble lizards, mimicking the appearance and behavior of toxic reptiles likely helps avoid predation. Amazingly, some blennies not only look like venomous coral reef lizards but also replicate their head-bobbing movements!
This type of mimicry, known as Batesian mimicry, enables the harmless mimics to fool predators into thinking they are the unpalatable models they resemble.
According to one fascinating study, blenny species that most closely resembled lizards experienced significantly lower predation rates compared to poor mimics. These convincing results provide strong evidence that natural selection has shaped coloration, body shape, and behavior in blennies to resemble lizards for protective benefits.
Ultimately, the fish that best imitated noxious lizards had higher survival odds and were more likely to pass on their genes.
Predator avoidance
Predator avoidance is a major advantage conferred by lizard-like appearances and actions in fish mimics. By resembling the form and behavior of toxic, bad-tasting reptiles, mimic fish deter potential predators.
For instance, coral reef fishes like lionfish, groupers, and wrasses prey less on convincing blenny mimics that exhibit lizard-like rocking motions. The predators likely mistake the mimics for genuine lizards and avoid them to prevent unpleasant encounters.
Field experiments have shown that simply attaching lizard skin or painted lizard replicas onto non-mimics significantly reduced predation. This demonstrates that predators actively avoid anything resembling a lizard’s scent, color patterns, or shape.
In fact, one fascinating study showed model lizards reduced fish predation by over 50%! This reveals how powerfully a lizard-like appearance protects fish from predators.
Foraging advantages
In addition to avoiding predation, resembling lizards may grant fish mimics foraging advantages. For example, some blennies can access confined spaces occupied by small invertebrate prey by imitating the head movements of reptiles.
Bobbing their heads side-to-side, they scare away prey from hiding spots, allowing them to more easily capture food.
Interestingly, some mimic species have evolved specialized fin structures on their heads that amplify lateral movements to better copy a lizard’s menacing head-shake. This innovative adaptation likely developed to improve foraging efficiency, further indicating the benefit of lizard-like mannerisms.
Additionally, mimics that successfully scare away small prey may gain access to food sources unavailable to other fish. Therefore, lizard mimicry offers mimic species unique predatory capabilities.
Conclusion
The amazing lizard-like fish found across the world’s oceans demonstrate the power of evolutionary adaptation. Their uncanny resemblance to land-based reptiles provides crucial survival and hunting benefits underwater.
By mimicking the appearance and motions of lizards, these fish are able to fool predators and prey to better navigate the daily challenges of life in the sea. The next time you come across an unusual fish that looks strikingly like a lizard, take a moment to appreciate the wonders of mimicry and evolution that allow it to thrive.
