Florida Croc hullabaloo!

Hi everyone. Sorry for not getting to this sooner. I was busy with the opening of the AMNH croc exhibit. It has been a fun couple of days but I think it is important to comment on the Florida crocs. in particular all of the "Maneating crocodiles in Florida" hype. 

First. We already have an existing crocodile in Florida. It is our very own native crocodile species, the American crocodile, C. acutus. It is slowly recovering from being decimated by overharvest and wetland conversion. It is certainly not doing as well as the American Alligator, also a native species that we take great pride in. ( Alligator mississippiensis- completely different critter, very distantly related to crocodiles- see earlier #crocmyths ).

Most of us croc researchers have known for some time that there were Nile crocodiles ( C. niloticus), in florida, because, like the Nile monitor lizards ( varanus niloticus), and pythons, they are are a big problem in the pet trade with lots of people buying cute little ones and then "freeing" them when they get too big and no zoos or museums will take them. Don't get me started on the pet trade in herps here. That's a topic for another day!

What the new paper did was to use DNA barcoding of a couple of individual crocs from Florida and compared against our data set from Hekkala et al 2011, to show that the Nile crocodiles in Florida's water ways all come from one area in South Africa. 

This is actually important for two reasons. First, it can be helpful in understanding the source for legal and illegal trade in protected species. Conservation geneticists do this a lot for tracking trade. 

Second, we can confirm that these released or escaped individuals are Nile crocodiles ( sometimes implicated in crocodiles attacks in Africa), and not our newly rediscovered sacred crocodiles from west Africa (Crocodylus suchus). This is hugely important because their ecologies are slightly different so that one species is potentially more likely to take hold in a new environment than the other. See my grad student Stephanie Dowell's amazing work on monitor lizards.  My former Grad Seth Cunningham and I are working on modeling invasiveness in niloticus and suchus. 

This is also important because C. suchus, the sacred croc, has been described as being relatively docile compared to C. niloticus. 

Finally, I will just re-iterate #crocmyth 2. Crocs aren't typically out to get humans. They do occasionally attack humans. Often in unfortunate circumstances where humans invade nesting areas or their food supply has been altered. See my very old NatGeo film "Man-eaters of Madagscar" for more on that. These few Nile crocodiles in Florida pose a MUCH greater risk to the American crocodile than to any humans. These two species share the same number of chromosomes and if they hybridized, we could actually lose our unique American crocodile, due to what is called genomic swamping. There isn't any evidence for this yet. 

Let's hope the research brings more attention to the problem of escaped and dumped non-native species in our waterways. not because of risk to humans, but to our ecosystems and the species in them.

In this case you were wondering, we know that one individual Nile crocodile was an accidental release from an amusement park ( FYI this happens all the time). 

Feel free to discuss! oh and don't do this.