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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