One of the programs I do with Florida Sea Grant is Restoring a Healthy Estuary.  There are four focus areas within this program: improving water quality, restoring habitat, managing invasive species, and enhancing wildlife.  For those who know me, they know that enhancing wildlife is near and dear to me.  My major in college was vertebrate zoology and I have been monitoring and teaching about vertebrates for 40 years.

I have found that the articles I write on this topic are my most popular, particularly snakes.  And I get that.  Whether you love them or hate them, snakes are interesting to read about.  As we roll into 2024, I thought I would do a series of articles on vertebrates I encounter as I conduct hikes/surveys on our barrier islands.  From a biogeographic view, barrier islands are interesting in understanding first, how some of the animals reached the island, and second, how they survive in a sandy/dry environment that is in many ways similar to deserts.

My first hike was just after the new year on the western end of Santa Rosa Island.  Wintertime is cold and the ectothermic vertebrates (amphibians and reptiles) are hard to find, most going dormant this time of year.  But, on sunny days when the wind is low, they can find places where they bask and stay warm.  If you encounter them, they will most likely not move quickly (they are still cold) and this provides a better opportunity to view them, though their coloration is very cryptic with the environment and, with little motion, you may miss them.  For the endothermic vertebrates (birds and mammals) this is their time.

On this warmer sunny January day, we spent several hours out.  There was not much movement other than a variety of songbirds.  Then we heard rustling in the woods under some live oak trees – it was an armadillo.

Many of us have encountered this interesting mammal.  You may not have recognized it as mammal, but it is.  As a lifelong resident of Pensacola, I know that prior to Hurricane Ivan there were fewer armadillos on Pensacola Beach.  They were there but in low numbers.  What was common at that time were striped skunks.  Since Ivan I have not seen a skunk.  I have asked park rangers at the Gulf Island National Seashore, and they have not seen them either.  But the number of armadillos immediately increased.  It seems the skunk left a niche open, and this animal took it.  Some say the armadillo may have increased in population whether the skunks were there or not – that is just armadillos.  So, who is this “new kid on the block” that has become so common on our islands?

Armadillos are native to central and south America.  They are a smaller mammal in the Order Cingulata and related to anteaters and sloths.  Mammals are divided into orders based on their dental formula (what type, and how many teeth they have).  In this sense armadillos are unique.  They have around 30 peg like teeth which they use to feed on insects, their larva, arachnids, snails, small vertebrates, and eggs – though reports of them raiding shorebird nests are rare.  They do eat cockroaches, which many people appreciate.  They acquire their food by digging into loose soil with their large claws.  This is one reason they do so well on our beaches and why many homeowners dislike them – they can destroy a yard to find prey.  Though they have poor eye site and hearing, which is noticeable when you encounter one, they have an excellent sense of smell.

Armadillos move relatively slowly seeking prey but when disturbed they can run quickly and swim well.  They dig round burrows, which I have found many on Santa Rosa Island.  Because they often share habitats with gopher tortoises, the burrows are often confused.  Armadillo burrows differ in that they are completely round.  With gopher tortoises the entrance is usually flat across the bottom and dome shaped across the top.  Armadillos usually spend the daytime in these burrows, foraging at night with more activity near dawn and dusk (crepuscular).

One secret to their success is their reproductive rate.  They breed in summer but hold off development of the embryo to allow a late winter birth.  They only have one litter each year but is almost always four identical young of the same sex.  This is because they develop from the same fertilized egg.

Diseases and parasites in armadillos are few compared to native mammals, rabies has not been documented. Leprosy has been documented in armadillos in Texas, Louisiana and Mississippi, but there have been no reports of infected ones in Florida.

The dispersal of armadillos from central to north America most likely occurred crossing the isthmus in Panama.  But there are reports of the animals being released in eastern Florida beginning in the 1920s.  It was noted that they were able to cross the Mississippi River in the 1920s when people began to build bridges for this new thing called the automobile.  Eventually the Florida and Texas populations merged.  They are dispersing north towards the Ohio Valley but are not fans of cold weather and this has been a barrier for further dispersal north.  We will see what climate change will do to their range.  They most likely reached our barrier islands by crossing bridges, though there are locations where the Intracoastal Waterway is narrow enough, and dredge spoil island frequent enough, they could have swam/island hoped their way over.  Either way they are here.

Many dislike this creature and would like to see them gone.  Some consider it an invasive species and needs to be managed.  Others find them cool and enjoy seeing them.  It was the only non-bird creature moving that day, despite the warmer weather, we will see what the next hike/survey will bring.

Reference

Schaefer, J.M., Hostetler, M. 2021. The Nine-Banded Armadillo (Dasypus novemcinctus). University of Florida EDIS Publication. https://edis.ifas.ufl.edu/publication/UW082.

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