Hidden in Plain Sight: Two New Crocodile Species Uncovered on Mexican Islands

Here’s a twist: two new crocodile species have been living on well-known Mexican islands, yet nobody realized they were different. Fresh coverage put the discovery back in the spotlight, reminding us how much of nature we still don’t see, even when it’s right in front of us.

American Crocodile (Crocodylus acutus) in La Manzanilla, Mexico. | Image by Tomas Castelazo, CC0, via Wikimedia Commons

What scientists found

Researchers say the newly recognized crocodiles live on Cozumel and on Banco Chinchorro, an atoll off Quintana Roo on the Caribbean side of Mexico. For years, locals and visitors assumed these reptiles were just the familiar American crocodile. Careful study showed otherwise.

According to McGill University, the team compared DNA from island crocs with samples from across the Caribbean and mainland coasts. They also examined skull shape and other anatomy. The result: the populations on Cozumel and Banco Chinchorro are distinct enough to count as separate species.

Why this matters for conservation

Small islands mean small populations. Early estimates suggest each new species has fewer than 1,000 breeding individuals. That’s not panic time, but it is a flashing yellow light. Limited range plus coastal development and tourism pressure can add up fast for island wildlife. As project lead, Hans Larsson put it, “Biodiversity is disappearing faster than we can discover what we’re losing.”

There’s another problem: because these crocs were long lumped in with the American crocodile (Crocodylus acutus), they haven’t had species-specific management. Now that they’re recognized as unique, conservation plans can be tailored to their habitats—mangrove lagoons, reef-fringed atoll shallows, and nesting beaches on two very different islands.

Hidden in plain sight

This story isn’t just about crocodiles. It shows how genetics can reveal “cryptic” species that look similar but are evolutionarily distinct. Island isolation drives that split. Over thousands of years, currents and geography cut populations off, and they evolve separately—even if to the naked eye they still look like their neighbors.

The researchers say the two species don’t yet have formal names; that step follows the taxonomic process now that the science is peer-reviewed. In the meantime, the focus is on safeguarding nesting sites and reducing disturbance where people, tourists, and crocodiles share the shoreline.

What happens next?

Expect a push for:

Targeted monitoring on Cozumel and Banco Chinchorro to size up population trends and nesting success.
Habitat protection in sensitive lagoons and beaches, especially where coastal building is accelerating.
Clear guidelines for tourism and research so visitors can spot crocs without stressing them or their nests.

Lead author José Avila-Cervantes called the findings “totally unexpected,” a reminder that even big, toothy reptiles can fly under the scientific radar. The team argues that recognizing these lineages is the first step to keeping them around.

Big picture: what it tells us about biodiversity

New species stories often feature tiny frogs or insects. But large animals can be misclassified too, especially when they look similar across wide ranges. This discovery updates how we map the family tree of Crocodylus in the Caribbean and nudges managers to treat these island crocs as priority populations. That shift—from “just a local variant” to “a species with a tiny range”—can unlock stronger protection and funding.

Why you should care

Healthy croc populations mean healthy wetlands. Crocodiles help control prey species, cycle nutrients, and shape habitats that also support fish, birds, and coral-linked food webs. When an island croc disappears, it’s a sign other pieces of the ecosystem are wobbling too. Recognizing these two lineages now gives conservationists a chance to act before the numbers slide.

The takeaway

Two new crocodile species—one on Cozumel, one on Banco Chinchorro—were hiding in plain sight. Today’s renewed coverage is a good prompt: if we want these reptiles to outlast us, we’ll need species-specific plans, smarter coastal development, and steady monitoring. The science is clear; the next move is ours.

Hidden in Plain Sight: Two New Crocodile Species Uncovered on Mexican Islands — What It Means for Conservation