Another Teenage Mutant Ninja Turtles movie is coming next year, featuring the heroic efforts of four giant mutated reptiles named after famous artists. Seeing the new trailer got me thinking: How can you tell a turtle’s age anyway, and from that could you age the members of the TMNT crew?
To find out, I contacted wildlife ecologist Dr. David Steen, an Assistant Research Professor at Auburn University. First of all, he told me in an email, aging a turtle isn’t an exact science. “But there is a trick you can use for a general estimate of a turtle’s age.”
That trick is looking at the turtle’s scutes, or the bony plates that come together to form its shell. If you look closely, those scutes have rings on them. And those rings, called annuli, are put down as the turtle ages. “Not unlike the rings you can see when you cut down a tree,” says Steen.
“You can count how many ‘growing seasons’ the turtle went through, which correspond more or less with its age in years.”
However, Steen cautions that this trick isn’t always effective. A shell’s scutes can be worn down with age (or fighting with a ninja dressed as a cheese grater), making aging more difficult.
What about Leonardo, Michelangelo, Donatello, and Raphael? Turtles reach sexual maturity a bit sooner than humans, at around 5 to 10 years old. “So I would expect to see that at least that many annuli,” says Steen. Five to ten annuli and you have teenage turtles.
But is that what we see? That’s hard to say because the movie turtles aren’t exactly meant to look like real reptiles (turtles would look pretty scary with lips). Though we do get a good look at Donatello’s scutes in the new trailer — scutes on the underside of a turtles are called plastron, but Steen thinks these could simply be “abs” — but it’s hard to make out much detail. “I can only make out about two annuli,” Steen told me, “So, I’d probably age Donatello as two years old.” This could be a result of wear-and-tear, or maybe we should change the song to “Toddler Mutant Ninja Turtles.”
“Unfortunately,” Steen concluded, “They’re all wearing pants so I can’t examine their cloacas to settle this conclusively.”