from the March 18, 2006 Newsletter issued from Diego Nuñez's office in Río Lagartos, northern Yucatán, MÉXICO
MORELET´S CROCODILES

photo by Elmer Canul of Río Lagartos, Yucatán

As soon as our van had pulled up to the dock at Dzilam de Bravo we saw a good-sized Morelet's Crocodile, CROCODYLUS MORELETII, floating in the much-boated canal right beside our busy road. The guides said it was a Morelet's but the reptile rode so low in the water and was so silhouetted that we couldn't distinguish it from an American Crocodile, which might conceivably appear in this area, or even an alligator, which shouldn't.

My herp book doesn't mention Morelet's Crocodiles existing in the northern Yucatan, so I asked the guides if maybe these crocs had been introduced here for the benefit of tourists. No, it was true that until a few years ago no crocodiles lived along this coast but then a big hurricane came along, Gilbert if they remembered correctly, and since then the crocs have been reproducing and spreading.

In fact, at the edge of one lagoon up the coast we saw a mound of sand about the size of a melted Volkswagen, and that was a crocodile nest. A few feet away at the water's edge, well camouflaged among mangrove stems, rested several babies maybe 15 inches long. At the reedy edge of one lagoon we saw where a very big adult had slid from the water onto dry land, smoothing mud and knocking down vegetation. Not one of the group could resist glancing behind us.

The guides told us that during the nights the hundreds or maybe thousands of flamingos across the lagoon flew elsewhere to roost. It's supposed that they go to crocodile-free lagoons.

You may be interested in looking over the tourist blurb I wrote about the Dzilam de Bravo trip at http://www.backyardnature.net/n/06/060318x.htm.

Also, I've put together a selected list of plants and animals of the Dzilam de Bravo Conservation Zone at http://www.backyardnature.net/yucatan/dzilamff.htm.

from the October 23, 2011Newsletter issued from Mayan Beach Garden Inn 20 kms north of Mahahual, Quintana Roo, México
CHRISTINA'S CROCODILE
The other day Newsletter reader Christina near Tulum in the Yucatán sent me some crocodile pictures, asking if I thought she had an American or a Morelet's Crocodile. It was hard to say from the pictures but in the end I figured it was probably a Morelet's, based mainly on the fact that its snout seemed wider than the American's, plus at her inland, swampy location near Tulum Morelet's is what you'd expect. Christina has put together an interesting and well illustrated blog about her family's experience with the croc here.

American Alligators are completely different from crocodiles. You can't see an alligator's teeth when its mouth is closed, but a crocodile's lower teeth are always visible. Also, the alligator's snout is much broader than a crocodile's.

American Crocodiles occur from extreme southern Florida south spottily along the coasts to northern South America, so the Yucatán fall within that distribution area. Morelet's Crocodiles occur only in southern Mexico, Belize and Guatemala. Along the Yucatán's eastern coast American Crocodiles occur mostly in mangroves, coastal lagoons and sand banks, while the Morelet's is found mostly inland in sinkholes, ponds, and flooded savannas.

If you want to know which of our two croc species you have, there's a way to figure it out. Keeping in mind that "maxillary teeth" are those arising in the upper jaw and that they're numbered from the front, Jonathan Campbell in Amphibians and Reptiles of Northern Guatemala, the Yucatán, and Belize tell us the following:

The American Crocodile's snout width at the tenth maxillary tooth is less than or equal to 70% of the distance from the base of the tenth maxillary tooth to the tip of the snout. In contrast, the Morelet's snout is wider -- at the tenth maxillary tooth the snout's width is greater than or equal to 75% of the distance from the base of the tenth maxillary tooth to the tip of the snout.

The tenth maxillary tooth coincides with the snout's constriction about midway the snout's length.