Sand Skinks
Plestiodon reynoldsi
Deep in the heart of Florida there's a series of ridges.
These ridges are known as 'Florida’s Ancient Islands' and are
the remains of ancient coastal dunes that stayed high and dry during thousands of years of fluctuating sea level.
While most of Florida was covered by ocean, these isolated ridges evolved into one of the world’s most unique habitats: scrub.
Most of Florida is humid, sub-tropical, and soggy,
receiving an average of 50 inches of rain a year.
But the scrub is different.
Rain filters right through the sandy ancient dune soil and straight
into the Floridan aquifer, instead of getting caught in drainage pipes,
bodies of water, soggy ground, or the ditch next to Walmart.
These sandy habitats serve as the primary recharge areas for
the aquifer. With all that rainwater seeping quickly through the
sandy soil, it leaves the scrub hot, dry, and desert-like.
Many of the species that adapted to live in the scrub are
found nowhere else in the world, making it a special
place of biological importance.
Years and years of isolation led to unique species
endemic (found only in a specific location) to these xeric (dry) habitats.
The sandy ridges of Central Florida house one of the highest populations of rare plants and animals species in the United States.
One of the rarest, weirdest, but raddest of all in scrubland is a creature that swims through sand.
Don't worry. They're nothing like the creatures from
Return of the Jedi, Tremors, Beetlejuice, or Dune.
Those are all sand worms.
Meet the sand skink.
Sand skinks are shy, small, greyish-tan lizards that are perfectly designed for sand swimming. They're about five inches long with slender, cylindrical bodies, tiny nub limbs, and smooth, shiny scales.
They also have wedged-shaped snouts, partially
countersunk lower jaws, small eyes with windows in lower lids,
and no external ear openings for sand to get caught in.
They are perfectly adapted for life in the sand.
Their tiny nub limbs are well-designed too.
With one toe each, the front limbs conveniently fold into a
perfectly limb-sized groove on the lower body.
Their hind limbs have two toes and are only slightly larger.
Their tails are super long! Half of their total body length.
Sand skinks are super cool.
But not when it comes to their needy living requirements.
They can be quite fussy.
They only live in 7 of the 67 counties in Florida.
(Osceola, Polk, Lake, Highlands, Putnam, Orange and Marion.)
The other counties are not up to their standards.
Sand skinks are a picky bunch:
They prefer to exist 82 feet above sea level. (81 isn’t good enough.)
Rosemary, sand pine, and oak scrubs, scrubby flatwoods, longleaf pine habitats, xeric hammocks, and turkey oak ridges are prime. (Citrus groves, former scrub, overgrown scrub, pine plantations, old fields,
and pastures will suffice as long as the soil suits their burrowing needs.)They desire large open patches of bare, loose, well-drained sand with no ground cover, plants or roots in the way.
Leaf litter is mandatory. It collects moisture and is an excellent place to hunt for larvae, termites, spiders, and other small invertebrates. But too much leaf litter blocks their burrowing needs.
Shade from shrubs and trees is needed for body temperature regulation. But only the right amount. Not too little. Not too much. And only next to their bare sand patches and leaf litter, not above.
Ecotones are the area between habitats like scrub and flatwoods that offer a lot of what sand skinks are looking for. Especially the ones found on the Mount Dora, Winter Haven, and Lake Wales Ridges. But that can be a hard bar to pass. Their food supply, leaf litter, shade needs, elevation, moisture levels, and sandy soil patches all have to be just right.
Historically, wildfires naturally maintained the habitats that sand skinks prefer. But for a host of reasons we now rely on prescribed fires. But even that challenges sand skinks. Burn too long or too little and it messes with their leaf litter desires. Good luck, burn bosses.
People rarely see sand skinks above the ground. But if you look for wavy tracks in the sand that seem like tiny snake slitherings,
it may just be a sand skink swimming underground!
Skinks typically don't stray more than eighty feet from their
sand tracks. They feed, breed, and shelter there, either on the
surface or five to ten centimeters down in sandy substrate.
When they find their favorite sandy patches with the perfect
amount of leaf litter and shade they don’t stray far from it.
Been spendin' most my life livin' in a
sand skink's paradise. -Skinkio
March through May is baby making season for sand skinks.
55 days after some successful kinky skinky, females lay
two eggs in sandy nests or under debris or logs.
The eggs hatch in June or July and like most reptiles, baby skinks
hatch with everything they need to be independent.
Two years later the baby sand skinks will be all grown up
and ready for the kinky skinky themselves. Most will live and breed
for a couple of years. Then the next generation will inherit the best sand patches around, sprinkled with the perfect amount of leaf litter.
At least that's the hope...
Unfortunately, sand skinks are struggling.
They are listed as a threatened species mostly because
of habitat loss. Turns out that sand patches are popular
with humans too. Two thirds of historical sand skink habitat
has been lost due to agriculture, residential uses,
phosphate mining, and the building of many, many Walmarts.
Lack of fire has also contributed to the overgrowth of
the sensitive, fire-needy habitats that sand skinks depend on.
Competition from non-native and invasive plant species
are a problem too. And the remaining good sand patches
are so fragmented that populations can’t find each other during
kinky skinky season, leaving genetic diversity a concern.
It's tragic that just as we're beginning to understand how complex and connected all species are, we're losing them at an alarming rate.
But hope remains for the sand skink and others. Because the more we learn and appreciate something, the more we love it.
And we want to protect what we love.
And what's not to love about the sand skink?
May the ridges of Central Florida forever provide the perfect sand patches, leaf litter, shade, moisture, elevation, and food levels to satisfy the exquisite taste of the sand skink. That way the awesome weirdness that lives on these amazingly unique, ancient sand dunes can be enjoyed for generations to come.
Long live the sand-swimming sand skink!
This comic was a final project for the
Florida Master Naturalist Program - Upland Systems.
www.crittercomics.com