Published: Jul 6, 2004
“We work on introduced species. These are species that are found
outside their normal native range.”
Dr. Todd Campbell’s blue eyes aren’t fully lit yet, but it won’t be long. If
the world ever has known a top-notch scientist who isn’t passionate and excited
by his work, Todd Campbell is not it. But at this point, he is merely warming to
the topic at hand—his recently launched efforts to eliminate the Nile monitor
lizard from the southwest Florida city of Cape Coral.
Not only is it really important to work on them because they’re second only
to habitat destruction in their affects on native species,” he continues,
momentum building, lights coming on, “and whole ecosystems can be altered by
these introduced species, but you can also ask a lot of interesting ecological
and evolutionary questions using introduced species, because you don’t need
permits to collect them. So, I try to do both basic work and applied work in
The applied work must be where the biggest fun is. This high-energy assistant
professor of biology hasn’t said as much, but he exudes it. And while the energy
is high and the delivery loquacious, both are keenly focused, always, and never
without significant substance. With all that waiting, the warm-up quickly spikes
into the good stuff.
The Human Condition
Two years ago,” Campbell says, knowing exactly where he’s going, “I was told
by a colleague that, during a trip to Miami to work on introduced lizards down
there, I need to stop in Cape Coral and see the Nile monitors, because it’s
really incredible what’s going on there. I didn’t know anything about
“OK,” Campbell remembers thinking, “I’ll stop there for a couple days, get a
hotel, and see if I can find some of these things.”
He admits to not expecting anything more than a minor population of
individual lizards that had been released by suburban yuppies who had grown
tired of the novelty of keeping their unruly exotic guests. But a surprise was
on the subtropical horizon.
“What I found was trails and boroughs and scared residents and people who had
had the things climbing on their roofs, eating their cats, taking goldfish out
of their ponds, and cornering them in their garages.
“So, it was really interesting to me,” he says, as if that weren’t
interesting enough, “from the human perspective, because studying introduced
species is not pure biology. By definition, you’re studying the human condition,
too, because we are the ones [responsible for introducing them]. If it’s an
introduced species, it hasn’t done it on its own.
“Not only do we have the fact that the pet trade and the people who buy these
things were the cause of this whole problem, but we’ve got this introduced
species impacting humans in a very big way.”
Poised for Growth
Contributing to the problem is the fact that the aggressive African lizards
thrive in their adopted habitat. Cape Coral is a residential former “bedroom
community” to Fort Myers that has grown to more than twice the population of its
older, better-known neighbor city. It extends over the southwest Florida
mangroves in a sprawling maze of partially developed neighborhoods interspersed
with canals and enclaves of undeveloped land.
Neighborhoods seem to spring up overnight like clumps of gleaming stucco
toadstools—but with plenty of space in between. Rather than fill vacant space
within neighborhoods, the trend from Port Charlotte to Cape Florida seems to be
to start more neighborhoods, while never quite finishing any of them.
The result is a low-density residential mini-metropolis almost as “full” of
vacant lots as it is houses, and Nile monitors just love vacant lots. They
especially are keen on Cape Coral’s vacant lots, which tend to be backed by
vegetated canal banks.
The city’s Web site lists a human population of 127,582, and boasts this
“With nearly 85,000 vacant home sites, 400 miles of canals, 3,236 miles of
paved streets, and the second-lowest crime rate in the state for cities of more
than 100,000 people, the Cape is poised for continued growth.”
Humans evidently aren’t the only ones who think so. But, while the site has
an “owl cam,” an “osprey cam” and an “eagle cam,” the “ Nile monitor cam” is
notably absent, and in fact, a search for “monitor” on capecoral.net turns up
only the verb.
The community initially was developed in the 1950s, although the city’s
population explosion didn’t hit until much later. Like so much of developed
Florida, the land was not suited for human habitation until developers decided
it could be, and took whatever measures were necessary to turn a swamp into a
“We call it ‘the scrape,’” says Campbell. “They basically took a marsh and a
mangrove habitat, and scraped it out, dug it up, and placed the material off to
the side to make uplands for building. As a result, you’ve got all these canals,
and the whole city is fringed with mangrove habitat.”
The vacant lots and fields bordered by canals give Nile monitors a perfect
place to call home, a home much more like their original habitat than any humans
in the area can claim. In actuality, two introduced species are pitted against
one another in a struggle for survival. For the humans, the situation might not
be quite that dire, but it is dire enough. And as so often is the case, they
have themselves to blame.
Tail Like a Bullwhip, Claws Like an
These are being sold at pet stores as little things like this,” Campbell
says, showing a photo of a cute and cuddly little lizard about the size of your
standard Florida gecko cradled gently in his hand.
“In a couple years, these things grow to a couple of feet, and they start
getting really, really aggressive, and by the time four or five years goes by,
you’ve got the five-footer that’s in my back yard.” (Yes, he had to keep just
one—in a sturdy wire cage. Name? Thumper.)
“What you’ve got,” he continues, “is this animal with a tail like a bullwhip
and claws like an eagle, and this business end up here,” he says, referring back
to the photograph and flicking a finger at the creature’s head, “with a serious
set of teeth. It can do a lot of damage.
“And they’re very-very-very bad pets,” he says with such sincere yet easy
intensity that the redundancy gets no quarter. “They’re just really-really awful
pets. People have them because of that reason sometimes—the big mean snakes and
the big mean lizards. It’s a very sort of sexy thing to have a big mean critter.
But they’re very bad pets, and the vast majority of people cannot handle an
animal like this after it gets big. They just can’t.
“And the pet trade is lying to the public. You can walk into any pet store
and ask them about the little hatchling Nile monitor that they have in a cage
for $39.95, if it’ll make a good pet, and they’ll just outright lie to you:
‘They only get four feet long. Oh, yeah, you can keep it in a 55-gallon
“I’ve even had pet store owners say, ‘No, they’re mean when they’re young,
and they actually mellow out with age,’ when the opposite is true. Only a very
small percentage of the public can handle an animal like this as a pet. So, they
No good scientist can stand a blanket generalization for long, and for
Campbell, his own is no exception.
“People who have pets and people who work in the pet trade industry have
various attitudes, and most people are generally good. But there are bad apples
out there, and some of those bad apples intentionally release animals to get
populations established. They can later cull from those populations without
having to deal with import laws and all that.”
As for ordinary residents who let the creatures go after they become
difficult to manage, Campbell’s outlook is a bit more forgiving, attributing a
combination of compassion, ignorance and, at worst, laziness to their
"Thumper" is unusually tame on this day, Campell says. Still, handling him
anytime is a handful, and Campbell recommends never trying it without heavy
gloves, patience and experience.
“They’re doing the wrong thing, but they’re
not doing it with malice, in general. They take the easy way out, and they let
it go, and that’s emotionally sometimes very fulfilling,” he says. “Some people
even think it’s the right thing to do: ‘Let it free! Let it free into the
environment!’ Well, most introduced species don’t have a big negative impact out
Most, he said, aren’t even able to establish themselves. Among those that
have, he cites monk parakeets, those bright green squawkers of Florida’s skies,
as an accidentally introduced species that is perfectly harmless. (They’re
harmless here, he points out. Evidently, some have spread north, and the noisy
winged beauties cause a lot of problems in, believe it or not, Chicago.)
As to why the Nile monitors are concentrated principally in Cape Coral,
Campbell can only speculate, but once again, he turns his suspicions to the
retail pet industry. Possibly, a pet store in the area enjoyed particularly
prolific sales of hatchlings. Perhaps more likely, someone saw pre-boom Cape
Coral, sans residences, as the ideal place to establish a Nile monitor
population that could be harvested for sales later. Again, the move would have
been strictly profit-driven.
“If you don’t have to ship an animal from Africa,” Campbell reasserts, “it’s
a lot cheaper—a whole lot cheaper to just go out and catch it. Here you’ve got
your African species—a big, sexy species like a Nile monitor—right here. You can
drive over to Cape Coral and catch them, and sell them for 300 bucks a pop. It’s
a very big incentive.
“We don’t know if that’s what happened,” he again is quick to add. “There
could have been a really bad tropical storm or hurricane that tipped over a
breeder’s cage. Maybe one individual got out, a female that was gravid, from a
breeding stock from a person who was very ethical.
“A lot of these invasions are totally unintentional. There are a number of
scenarios you can imagine. It could be simply the random, chance occurrence that
enough people bought these things from a pet store in the area and found them
bad pets, and decided Cape Coral would be a really good place to let them go,
because there weren’t very many houses. And eventually, given the large home
range of these lizards, they started finding each other.
“The monk parakeet population that’s all over Florida literally is the result
of a spill at the airport,” he says, returning to a favorite for illustration.
“A cage broke open, and all the birds got out. It was one event.”
Hurricane historian Jay Barnes notes in Florida’s Hurricane History
(University of North Carolina Press, 1998) that certain types of animals seem to
get unearthed and redistributed by major storms.
“Alligators, snakes and rats were a menace in the weeks after the storm.
Numerous snakebites were reported, mostly from the reptiles that had taken up
residence in homes and furnishings. One truck driver had operated his vehicle
for three days before discovering a rattlesnake coiled under the seat. The
proliferation of rats was a health concern and prompted the state to implement a
rodent control program. Five thousand pieces of poisoned meat were distributed
over south Florida by boat and helicopter in an effort to exterminate the
The passage is about Hurricane Donna, which blasted straight through the
region in September 1960. While that storm came far too early to have delivered
the monitors to southwest Florida (Campbell believes that the monitor invasion
likely began in the area in about 1990) a certain infamous category-four monster
named Andrew devastated south Florida in August 1992.
Could Florida’s biggest introduced-species headache be partly a long-range
residual of its worst storm disaster? The timing is close, and the proximity is
tantalizing, but the rest still is guesswork, and Campbell is certain the
invasion began no later than 1990.
And either way, says Campbell, blame ultimately falls on one source.
“I’m really angry at the pet industry for putting me in a position to have to
kill these spectacular animals,” he says, “whether it was intentional or
No Flying Lizards
In any event, somehow, circa 1990, a Nile monitor invasion of Cape Coral
began. There is no real guess as to how many may have been turned loose since,
and in that decade-plus, procreation naturally has added to the ranks. A single
female Nile monitor, Campbell says, may lay in excess of 60 eggs a year in
maturity (starting at about 4-5 years of age), and a single “clutch” of 84 eggs
has been recorded.
“They can reach reproductive maturity in two years,” Campbell says, at which
time the typical adolescent female monitor will set down a first clutch of about
Besides being obviously prolific, the hardy lizard also boasts a home range
of two square miles, and can hold its breath for an hour at a time. It also is
an outstanding swimmer and an expert climber. Hatchlings, in particular, spend
most of their time in trees.
In fact, adds Campbell, “About the only thing they don’t do is fly.”
Without a thriving industry that harvests them for food and skins (one
country in Africa eliminates some 800,000 of them each year in those pursuits,
Campbell says), the Lee County Nile monitor supplies the second major population
boom in the area.
Adding to their threat, as well as to their survival potential, is their
“They eat anything,” Campbell says. “Any kind of invertebrate—snails, clams,
even oysters in some areas; any other kind of crustacean, crabs, fish,
amphibians, reptiles, birds and mammals.”
They also are fond, he says, of bird eggs. They will eat burrowing owls and
gopher tortoises, and as if to give deeper meaning to the phrase “eating them
out of house and home,” will then take over the burrows excavated by their
latest victims. Turtle eggs are on the menu, too, and in their native Africa,
even dwarf crocodiles have been known to constitute meals for Nile monitors.
Smaller American alligators may be at risk, Campbell says, returning to the
dangers that monitors pose to indigenous species in Florida. He adds that no
positive impact speaks in favor of the lizards, “except for maybe the chance to
see a really incredible animal in the open. But that’s what zoos are for.”
From Big News to a Really Bad
Reaction to the eradication project came swiftly. Campbell and his colleagues
sent out a press release to Fort Myers-Cape Coral area news media. That the
story ever became national news may have been a bigger surprise than the news
“Our idea was to contact the local press, so that we could have an article in
the local newspaper, so that local people would call us back with monitor
sightings. Very clear goal in mind: We wanted monitor sightings so we could go
to people’s houses and set traps, try to catch these things, find out
information about their reproduction, maybe their density, and get an idea of
the magnitude of the problem quickly.”
The Associated Press liked the story enough to pick it up from the Fort Myers
News-Press, and before Campbell knew it, he was getting calls from family in San
Francisco and Kansas City by the next day, and e-mails from people in Canada who
had read the story.
Animal Planet and National Geographic were next, followed by National Public
Radio (on which he since has appeared three times) and PBS in Atlanta. The
chaser came when Jay Leno used the story for a joke in a Tonight Show monologue
“It was a really bad joke,” Campbell whispers, one hand to the side of his
mouth in a mock effort to keep the whole affair a secret. “I don’t even remember
the joke,” he concludes, still in a whisper, “but it was really bad.”
Bad jokes aside, Campbell appreciates the attention for the sake of his
profession and its work.
“It’s nice, because it’s very rare for people in my field to get a lot of
media attention. A lot of times, biologists do their work in isolation and
objectivity, and rightly so. It’s supposed to be an objective thing, but
conservation biology adds another whole level to science.
“You’ve got the science end of it, but you’ve also got an advocacy end of it,
a subjective end where you’re trying to manage populations. If Nile monitor
populations are bad, then it’s our duty to try to drum up support for somehow
fixing the problem.”
Big Bad Players
Funded by $30,000 from the National Fish and Wildlife Foundation and another
$20,000 from the Charlotte Harbor National Estuary Program, Campbell has built a
small team to work the problem with him. So far, his cohorts include fellow UT
assistant biology professor Mason Meers, herpetology Ph.D. candidate and
part-time trapper Gregg Klowden from the University of Florida, and full-time
trapper Zach Reffner of Cape Coral, and a pair of UT biology majors, Nathalie
Briend and Anthony Chacour, just added to the mix as research
Predictably, some well-meaning individuals and groups do not
like the work they have set out to do, which is to eradicate the Nile monitor in
southwest Florida by the only available means, which is to trap them and
humanely dispatch them with gas. (The latter chore is performed “ethically,”
Campbell says, by a local veterinarian.)
“Three weeks after we started this project, there was a ‘Save the Nile
Monitor Society’ in Fort Myers,” Campbell recalls.
The Fort Myers Herpetological Society even organized excursions to see the
“An hour after the first press release that we did, PETA—People for the
Ethical Treatment of Animals—called. From their standpoint, it’s not the
“But it’s also not the native species’ fault, either, and so, if we’re going
to have to make a choice, we’re going to go with the native species. We don’t
want, in any case, an introduced species to be the nail in the coffin of a
“Some of these introduced species are really big bad players. They’ve caused
literally the extinction of species. There are a 150 species of cichlid fish in
Africa—the pretty cichlid fish that you would see in pet stores—that are gone
now, gone forever, because of the introduction of the Nile perch into one lake
Campbell says at least one indigenous Florida species is at significant
“It’s possible that Nile monitors could affect burrowing owls pretty
Presumably, he says, Nile monitor hatchlings are vulnerable to alligators and
hawks, but their density and propensity to procreate continue to increase their
population, and once past the hatchling stage, there is little they have to fear
from other species, with the exception of humans and adult alligators, both of
which they can usually outrun or outmaneuver.
“They’re getting abundant enough,” he says of the monitors. “Their density is
reaching that of what you would see in Africa. They’re the top predator in this
A Difficult Find
Confident that the lizards in fact number in the thousands in Cape Coral,
Campbell and company have a difficult time encountering as many as residents
seem to just by chance. The reason?
“They’re really smart,” Campbell declares. “They’re really intelligent
lizards. They’re actually really intelligent even for some mammals. They control
their world and what they are going to do. Most people don’t see them because of
that—because they hear you coming, and they take off. They can run 18 miles an
“It was very hard for us to figure out how to go look for them and find them.
Generally, what we wound up doing is walking along the canal banks, and just
very carefully approaching, and you can actually get a glimpse of them before
they go in the water.”
Ironically, as Cape Coral stops spreading and starts filling in its empty
spaces, the situation naturally will improve for that area. It’s what’s beyond
that concerns the scientists.
“The sea-walling of all the canals is going to diminish the habitat for Nile
monitors,” Campbell asserts, “so as build-out in this area occurs and the more
seawalls there are, the less habitat there is for Nile monitors to burrow. So,
it’ll get better as time goes on.
“But what we’re worried about is the monitors moving out of Cape Coral, and
moving north, or just their population generally expanding and spreading out in
concentric waves, just like any population would.”
The Only Answer
Eradication is the only viable answer, Campbell says, and there is no time
like the present.
“With introduced species, the big mantra is ‘too little, too late.’ In almost
every case, we look back at an introduction, and we say, ‘Gosh! If only we had
had stronger quarantine methods at that time,’ or, ‘I remember when there was
only a small population.’
“Given a reasonable amount of resources, like a small team of biologists and
trappers, I think we can actually get rid of this population here, if they
haven’t spread out into the natural areas too much.”
But if they have?
“Then we do have a too-little, too-late situation.”
And already, it appears that Cape Coral may not be the only trouble spot.
“There’s a population, we think, in Orlando. There’s a population in
The more we find out, the worse it sounds like it’s getting. There may be
other populations established on the east coast, maybe even [elsewhere] on the
west coast of Florida.
There have been a few sightings in Hillsborough County, he says.
“We don’t quite know about their geographic distribution yet. That’s another
thing we’re trying to ask. Where are they? How far have they spread?
“These guys can walk easily a mile in a day. So presumably, if they ate
themselves out of house and home in the general area of Cape Coral, and
everybody’s cats were gone, and there were no more bunnies to eat, they could
move pretty far.”
Fewer than 50 have been captured so far, but the trapping didn’t begin until
January, and Nile monitors tend not to eat in cold weather.
“Thumper hasn’t eaten in a couple of months,” says Campbell.
Even though the project began in July, the first catch with bait was in early
February. The early months were devoted to analysis and strategy. By the time a
plan was in place, the weather had cooled down, and mating season (which
evidently doubles as eating season) had run its course.
But as the weather warms up again this year, Campbell believes, the Nile
monitors will warm up to the bait. Summer, he predicts, will spell major
numerical success in the trapping effort.
“They’re going to start trying to put on weight and body mass for breeding,”
“Luckily, they’re pretty easy to catch with squid—the stinkier, the better.
If that weren’t the case, there’s no way I would even try this.”
Beyond the immediate solution, Campbell also must consider the future. The
last thing he wants is to finish eradication in one region only to be called
upon to start over in another.
“If I have it my way, Nile monitors will be illegal to own. Other monitors
are fine. Those other species are tamable. Croc monitors are nice. A savannah
monitor is a wonderful pet. The same goes for a water monitor. They’re nice
pets, so people don’t let them go.”