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03/06/2003
Wayward Wanderers and a Deficient Frog
This is my last column from sunny Marco Island in Southwest
Florida. Because of the many columns I have written on marine-
and beach-related topics, you might assume that I am a “water
person”. On the contrary, in all the years we have been coming
to Marco, I can recall only one time when I dipped a foot into the
Gulf of Mexico. At home in New Jersey, we belong to a swim
club that my wife has enjoyed for many years. I have only been
on the grounds for picnics or other social functions. My
reticence to test the waters of the Gulf here on Marco has been
prompted by the wildlife washed up on the beach, notably some
large jellyfish. Our nephew, a fishing enthusiast, points out that
there are also sharks in these waters.
I had no idea that there were any whales in the area. However, a
week or so ago, a baby whale beached itself on a beach in nearby
Naples. According to an article in the Naples Daily News, an
expert in marine life happened to be among the first to find the
poor little guy. The whale was diagnosed as having a twisted
intestine that would have led to its demise. That being the case,
the whale was allowed to expire on the beach. The newspaper
article said that the sick whale beached itself in a search for
shallow water so that its weight could be supported on a sandbar.
Could that be an explanation for other whale beachings? I have
no idea but may look into the matter.
Another incident was much closer to home. I typically hit the
beach around 6 AM so as to get my walk in before the sun comes
up too strongly. At that hour, there is usually enough light from
the moon or distant hotels to allow me to walk without stepping
in some child’s sand sculpture from the previous day. Aside
from this hazard of a possible twisted ankle or broken leg, I have
not been prepared for anything more sinister. Yet the front page
of today’s Naples Daily News features a picture of a seven-foot
alligator swimming and surfacing in the Gulf just off the beach
where I normally walk. The alligator was discovered early in the
afternoon and the beach was closed, on a beautiful sunny day,
while a licensed alligator trapper plied his craft. It wasn’t until
evening that the trapper netted his prey. As with the whale, it
was deemed that the creature should be dispatched. The alligator
had become too familiar with humans and posed a danger to life
and limb. Indeed, another story that drew media attention here
recently concerned another Florida alligator that chewed off a
woman’s arm while she was doing her gardening!
I have seen a fair number of alligators in Florida, on golf courses
and other venues. I was under the impression that one need not
worry about any in saltwater. According to the news article, an
alligator has no problem with saltwater. Being an air breather, it
just comes to the surface to inhale. However, saltwater is more
buoyant than freshwater and the alligator can’t dive as fast and as
agilely as in freshwater. How does an alligator get into the Gulf?
Occasionally, a gator in a bay is swept out to sea by an outgoing
tide. The article brought to light another fact that I hadn’t been
aware of. There are saltwater crocodiles in the area here in a
place called Rookery Bay. One of those guys caused a stir about
ten years ago when it wandered down to a beach off Naples’
fashionable Fifth Avenue. I don’t relish being in close proximity
to either species and will certainly be more alert if we’re here
next year.
The news article cited one characteristic of an alligator that really
shocked me. The article said that a gator can maintain a speed of
35 miles an hour for one mile. If I had known that, I don’t think
I would ever have played golf in Florida. The fastest humans
over the course of a mile only run in the neighborhood of15miles
an hour. Being skeptical of the 35-mph claim, I surfed the Web
looking for a definitive answer. One guru on a question/answer
site, in response to this question, said that he had heard that an
alligator runs 35 mph. This didn’t sound authoritative to me. I
found a more reasonable figure on the “Truckin’ FLA” site,
billed as “a trucker’s guide to the Sunshine State”. Here the
gator’s maximum running speed on land is cited as being a more
reasonable 11 mph. I’m not going to argue with a trucker. I also
learned that alligators open their mouths upward while crocs
open them downward. I’m going to have to leave you now; it’s
time to pack to go back home. ……………………..
I’m back in New Jersey now. How to finish this column? In line
with the aquatic theme, the January 24 2003 issue of Science
contained a brief item about a strange species of frog. The item
was titled “Tongueless Wonder”. Xenopus, the frog in question,
has no tongue! One of the marvels of the typical frog is that
rapid flick of the tongue to reel in its prey. Having never heard
of a frog without a tongue, I was surprised to find when I
searched the Web there were some 5,000 sites or references to
Xenopus, a well-studied frog. It seems that Xenopus, also called
the African clawed frog, relies on its front legs and/or sucking to
grab its victims.
In an ordinary frog, the rapid flick of the tongue is made possible
by a connection between the brain and the tongue muscles
through what is known as the hypoglossal nerve. Xenopus, with
no tongue, would not seem to need this nerve. At least that’s
what biologists have thought for years. Enter Idaho State
University senior Jamie Wiklund and Curtis Anderson, a
neuroethologist at that institution. They added a dye to the nerve
endings in the back of Xenopus’ mouth and waited a few hours.
The dye was taken up by a nerve and traveled to the brain, where
it connected to just the place that the hypoglossal nerve connects
in amphibians having tongues. The assumption at this point is
that the nerve has some function(s) other than flicking out a
tongue, perhaps assisting in breathing and sensory perception and
perhaps swallowing.
While this finding is no doubt important to biologists, I was more
interested in other features of Xenopus. Visits to the University
of Michigan and Arizona Web sites, revealed that Xenopus is an
amazingly hardy frog and is considered somewhat of a menace in
some quarters. For example, in a dry period it may burrow into
the mud, leaving a tunnel through which to breathe, and lay
dormant for up to a year. There are Federal and State laws
prohibiting the release of Xenopus into ponds and streams in this
country for fear that the hardy Xenopus will take over from the
native species. You’re in violation of the law if you take one
home as a pet.
As with the alligator speed, I’m in a bit of a quandary about the
“tongueless” Xenopus. The University of Arizona Web site
refers to the tongue of the normal frog or toad as being attached
at the front of the mouth and folded back. This arrangement
enables the unfolding and flicking out of the tongue to catch its
prey. However, Xenopus is cited as an exception, with “the
tongue completely attached to the floor of the mouth.” So, does
Xenopus have a tongue or not? Hey, it makes a better story if it
does not!
Finally, our heartfelt wishes to our Lamb creator Harry
Trumbore for a continuation of his remarkable progress towards
recovery from his unusual illness. Similar wishes go out to my
brother Conrad in his quest to solve his own medical problem
and to our grandson Douglas who, we just learned an hour ago,
has pneumonia! What next?
Allen F. Bortrum
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