JIM CONRAD'S
NATURALIST NEWSLETTER
Written at Hacienda San Juan Lizarraga
one kilometer east of Telchac Pueblo, Yucatán, MÉXICO
and issued from Hotel Reef Yucatan 13 kms to the north

December 15, 2005

HORSESHOE CRABS
Each week the beach is different from every other week. Often I find washed-up, dead organisms that I am completely at a loss to identify -- sometimes don't even know whether they are plants or animals. It's clear that just offshore there's an ecosystem as diverse and beautiful as any I've known, but it's beyond my reach. Still, I'm savoring the process of slowly discovering what I can about this mysterious, potent place.

This week's beach was different from all previous ones in that there were more shells -- extensive accumulations of them in mint condition -- washed up than ever before. Also, for some reason, strewn randomly along the beach, there were about a dozen dead, wave-deposited Horseshoe Crabs, LIMULUS POLYPHEMUS. Usually I find only one or two of them. You can see a picture of one, taken by my Natchez friend Karen during her visit here last spring, at http://www.backyardnature.net/yucatan/horscrab.jpg.

Crabs feed on clams, worms and other invertebrates, but if you look at Karen's picture you're likely to wonder where the mouth is. It's on the shell's underside in the center where the legs come together. Tiny projections at the legs' bases help grind larger itmes so they can enter the mouth. More info on Horseshoe Crab anatomy and many other topics relating to them is available at the Horseshoe Crab Website at http://www.horseshoecrab.org.

If you are familiar with the leggy, fast-moving, claw-flaunting crabs along most beaches you might guess that Horseshoe Crabs aren't crabs at all, but rather their own kind of thing. In fact, they're a very ancient creation more related to spiders than to crabs. They're closely related to trilobites, which often show up as fossils in older geologic strata. At one time trilobites were among the most conspicuous of Earth's life forms. During the massive extinction at the end of the Paleozoic Era (when 50% of all the Earth's animal families and 95% of all marine species disappeared for reasons still not clear) trilobites went extinct but their relatives the horseshoe crabs did not.

Anatomically, Horseshoe Crabs haven't changed much for the last 350-400 million years -- since well before the supercontinent Pangea began breaking into the continents we recognize today, even before the first amphibians arose from early reptiles. Horseshoe crabs are living fossils and when I find them along the beach I get a feeling like the one that comes in museums when I see fastidiously wrought but rather klutzy looking knight armor from the Middle Ages.

*****

THE YUCATAN'S SEA TURTLES
A week ago about 50 Mexican sea-turtle specialists, mostly academicians and administrators, met here to discuss the sea turtle situation. The local paper did a story on the meeting and from that and other sources I learn the following about the Yucatan Peninsula's sea turtles.

In terms of providing sea turtle nesting sites, the Yucatan is the planet's fourth most important location. Five of the Earth's eight sea turtle species nest or feed here. Our three nesting species are:

# Carey (also called Hawksbill)
# Green
# Caguama (also called Loggerhead)

The fourth and fifth species nest on other Mexican shores but can be found feeding here. They are:

# Kemp's Ridley
# Leatherback

A few Newsletters back I mentioned finding a small, dead small sea turtle on the beach here. Apparently many such dead turtles are turning up. The assumed cause is their getting caught in fishermen's nets. Of course sea turtles, being reptiles, breathe air, so, if they are caught in a net and can't surface, they'll drown. When you see how many fishermen in the waters off Hotel Reef tend their nets you wonder that any escape.

Large numbers of sea turtles are also killed here intentionally. The Carey, described as being in critical danger of extinction, is killed mainly for its shell, while the White is killed for its meat.

Along the Yucatan Peninsula's beaches about 30 known nesting zones are monitored by volunteers. Over the last 15 years about 45,000 nests have been identified both for the Carey and the White. These ±90,000 nests during this time have held some 12,500,000 eggs from which more than 8,000,000 baby turtles have been hatched.

More info about sea turtles, including distribution maps and estimated numberers for each species is at http://www.cccturtle.org/turtle-information.htm.

*****

A YUCATAN BANDED GECKO
One night this week arriving late from Hotel Reef I found the most beautiful and colorful of all of Yucatan's lizardy animals crawling beneath my big wooden doors into my room. It was the Yucatan Banded Gecko, COLEONYX ELEGANS, which you can see at http://www.geckosunlimited.com/elegans.htm,

I think he may have been stuck beneath the door, for when I opened the door a bit more he just lay there as if he were a little dazed, allowing me to pick him up for a good look. From the first glance it was clear that this was an unusual gecko species.

Most geckos possess paddle-like toe tips equipped with special scales enabling them to climb walls. This gecko's toes were sharply pointed and he couldn't climb walls. He was strictly a terrestrial species. Our other native gecko species lack moveable eyelids, yet this one had them. Also unusual for a gecko, the pupils of this one's eyes were narrow, vertical slits instead of round ones. When I let the little critter go he walked away making a very soft, catlike mewing sound, very unlike the obstreperous call I told you about last week made by my Common House Geckos.

Since this species was so strikingly patterned I figured the local people would regard it as deadly. The next morning I showed a picture of the species to Roberto the gardener and I wasn't disappointed:

"This is the most dangerous one we have," he assured me. "It stings with its tail."

Of course none of our geckos or lizard-like creatures sting with their tails and none is dangerous in the least, except possibly our Black Iguanas, which are so large (nearly three feet) that they can inflict painful but non-venomous bites. (In self defense one got hold of the throat of the hacienda's main iguana- chasing dog the other day and Roberto and Francisco had to pry its mouth open!)

Probably the reason people here say this gecko stings with its tail is that when it feels endangered it raises its body by straightening its legs, inflates its throat, and waves its tail ominously but innocently.

Yucatan Banded Geckos have a fairly limited distribution, occurring only in southern Mexico's lowlands into Guatemala and Belize.

*****

GRAY CRACKERS
The most conspicuous butterfly at the hacienda is not the Monarch I told you about some time back but rather a fairly large one with black-and-white, calico-like patterning. It's known around here as "Tronadora," meaning "Thunderer," and in English it's called the Gray Cracker. It's HAMADRYAS FEBRUA, a member of the family Nymphalidae. You can see one at http://www.backyardnature.net/nbr/b12.htm.

Several nicely camouflaged Gray Crackers usually can be found perching flat-winged on the gray trunks of the tall Royal Palms along the road leading into the Big House. By "flat-winged" I mean that they perch with their wings flat against the smooth trunk, like a moth, not held above their backs like normal butterflies. This fact alone makes the species unusual.

The names suggest something else unusual about it ("cracker" as in "cracking sound"). Another Gray Cracker will fly by, or maybe nothing will fly by at all, and the butterfly launches into the air in a very conspicuous and aggressive manner. As he darts about almost too fast for the eyes to follow sometimes you hear surprisingly loud snapping sounds like those made by some grasshoppers when they fly up from the grass in late summer. Most flights seem to be made to check out other Gray Crackers, maybe to see if they are the opposite sex, but possibly they may be males defending territories against other males.

On cool mornings when dew still lies heavily on things, it's easy to approach to within inches of a Gray Cracker on a palm trunk for a good look. However, once they bask awhile in the sun they get nervous and are very quick to take flight at the slightest provocation.

*****

BEER, BANANAS AND THE CHOOCH TREE
The other day I mentioned to Francisco that the bananas on one of our trees were about to ripen. The bananas are of a seldom-encountered variety, only about finger long, bearing purple peelings and with a very sweet, nutty-flavored flesh.

"You eat that banana while drinking a beer and it'll kill you," Francisco said in all seriousness.

I can well imagine how this belief got started. The funny thing is, though, I may be contributing to a similar superstition myself.

Outside my door there's an old tree called Chooch in Maya producing a spherical, grapefruit-size, orange- yellow fruit with soft, orange flesh and two or three shining, white seeds. In English the tree is sometimes called Canistel. It's POUTERIA GLOMERATA of the Sapotaceae, and you can see the very tree (it's the dense, green tree to the right of the red house) at http://www.backyardnature.net/travel/sj-c-chi.jpg.

Since the books say that the Chooch's fruits are edible and sweet and I'd never eaten one, when ours began ripening soon after my arrival I ate one, liked it a lot, and ate yet another.

The next day, for the first time in many years, I was genuinely sick -- weak, dizzy, vomiting, stomach pain, diarrhea and even painful urination. My Maya friends said my Chooch fruits must have been too immature. Probably they were, though I considered the flesh soft and sweet enough.

While talking to my friends about the Chooch fruits I learned that no one here eats them. The large, pretty fruits simply fall to the ground where iguanas devour them with relish. Well, if the fruits taste good and don't make you sick when they're ripe, then why don't people here eat them? I pestered people with that question until one day someone revealed that a few years ago a much-liked individual in the community committed suicide by hanging himself from this very Chooch tree.

So, maybe the locals' reason for avoiding the Chooch tree's sweet fruits has less to do with taste than with its association with that sad event.

To exorcize the old tree's bad aura, one day I decided to pick up a decidedly ripe fruit beneath the tree and eat it right there.

However, the instant the fruit's distinctive odor entered my nose, my stomach tied itself into a knot and a cold chill ran through my body. Surely it was the same case as when a child eats a bad peach or a sour grape when young and then henceforward can't bear to eat that thing ever again.

Even understanding this, for weeks I've been trying in vain to overcome my body's revulsion to Chooch fruits. I simply can't get the tiniest bite into my mouth without gagging. What an experience for one who considers himself to be so self disciplined and able to endure pain and inconveniences.

My experience with Chooch fruits gives me the creeps. It lets me know just how intimately the rational mind is entangled with the irrational. It suggests that mankind's never-ending struggle between knowledge and ignorance, benevolence and malevolence, the spiritual mind and the carnal body... may be trickier and harder than I'd like to believe.

This week I heard over the BBC that in Kansas people in control of the state school board are bent on changing the definition of science so that it no longer relates strictly to natural phenomena. They want it to embrace supernatural phenomena. Such must be the case if they successfully make it obligatory in Kansas for right-wing, evangelical Christianity's "Intelligent Design" to be taught IN SCIENCE CLASSES along with biological evolution to explain how the Earth's plants and animals got to be what they are.

Hearing that, my guts twisted into a Chooch-fruit-size knot and cold chills ran through my body. It was as if our Golden Age of Reason had got hold of one of those stubby, purple bananas while drinking a beer.

*****

Best wishes to all Newsletter subscribers,

Jim

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