While visual mimicry is covered extensively in the literature of evolutionary biology, in recent years, acoustic mimicry has been gaining a lot of interest. Lyrebirds and mockingbirds can copy almost any sound they hear to both deter predators and attract prey. Margays imitate the call of infant monkeys to attract and ambush the curious adult primates. And most domestic cat owners likely don’t know their little fluffball is playing them as a dupe, having evolved a meow at the same frequency as an infant’s cry, which pulls at the heart strings and often gets them whatever they want.

Using aquatic examples to appeal to Elsa’s sensibilities, he said, “The oceans are filled with copycat species that use mimicry to their advantage. I’m sure you’re familiar with the mimic octopus. To avoid predators, it impersonates the appearance and behaviors of a wide range of venomous or bad-tasting sea creatures. Contrary, to attract prey, the anglerfish uses its spiny protrusion and bioluminescent growth to lure and devour other small fish.”

“And merfolk?” she replied dubiously. “They mimic other creatures to…?”

Marty shrugged. “I don’t know if they would use some sort of defensive mimicry to fool larger predators in the oceans, but after hearing what we did, the way they imitated your voice, I’m quite positive they use aggressive mimicry for predation.”

“You’re saying those two merfolk were imitating my voice in the hopes of luring me to the water’s edge?”

“Or close enough to the water so they could strike with a spear. It sounds fantastical, doesn’t it? But there’s a historical precedence of merfolk-like creatures luring humans to their deaths. Look no further than Homer’s Odyssey. The sirens he writes about lured Odysseus’ sailors to their graves with seductive songs. Was that merely Greek folklore? Or was it based on some semblance of truth? Were the sirens in fact merfolk using not their songs—which would involve a comprehension and appreciation of music, which seems to be a uniquely human trait—but our songs, which they heard and stole from us?”

Elsa began shaking her head, but Marty plowed on: “Look, this is all speculation. I haven’t thought it through. But damned if it’s not possible. And here’s something else: the ability to mimic prey would solve the riddle of how merfolk secured a meat-rich diet to evolve and sustain their large brains. They lack dorsal fins and flippers like dolphins and other marine mammals, which means they’re almost certainly not fast or agile swimmers. But if they could lure fish, squid, octopi, and other prey to them via acoustic mimicry…well, there you go! A constant, easy supply of protein.”