Alligator Adventures

By Tom R. Johnson | November 2, 1995
From Missouri Conservationist: Nov 1995

Alligator snapping turtles live only in the few natural aquatic habitats remaining in the Bootheel.

The alligator snapping turtle, Macroclemys temminckii, is the largest species of freshwater turtle in the world. It also may be the most shy.

You might think such a large reptile would be easy to catch and study. But few herpetologists (people who study amphibians or reptiles) have tried to study alligator snapping turtles because they are difficult to capture or observe in the wild...they just don't show themselves often.

Of course, this is not the only "snapper" in Missouri. A smaller and more numerous species, the common snapping turtle (chelydra serpentina), is found all over the state and is sometimes confused with its larger cousin. The common snapping turtle rarely gets to be more than 30 pounds. Also, the head of a full-grown common snapping turtle is proportionally much smaller than the head of an alligator snapping turtle with the same shell size.

Alligator snapping turtles live in southeastern and extreme southern Missouri. Most of their time is spent in the water. Females leave the water only to lay their eggs during June or early July every other year. Alligator snappers live in rivers and old river channels (oxbow lakes) where they capture fish to eat. They also eat other kinds of turtles!

The record alligator snapper is a 219-pound male captured in southern Georgia many years ago. Adult males are over twice the weight of females. A few Missouri specimens weighing more than 120 pounds have been captured. A turtle this big can have an upper shell length of nearly 24 inches.

Alligator snapping turtles have the unusual (for a reptile) behavior of luring fish to their mouth with a pink tip on the end of their tongue. With its mouth wide open, an alligator snapping turtle will remain motionless and wiggle its wormlike tongue when a fish swims by. If the fish tries to grab the worm it is, instead, grabbed by the turtle with a powerful lunge.

The alligator snapping turtle is rare in our state due to habitat loss and illegal harvesting. There is no open season for this reptile. I've had some people tell me that alligator snapping turtles, especially big ones, used to be more common in the Bootheel, even up until the 1960s.

One elderly gentleman who I met near Kennett a few years ago told me his Daddy snagged one out of the St. Francis River that was bigger than a washtub. When I asked him how long ago that was, he said "Fifty years and then some."

The Conservation Department is interested in more up-to-date information on the status of this impressive reptile, and so, since 1983, we have been conducting two "mark and release" programs in southeast Missouri. These surveys were designed to help determine the turtle's distribution and population size.

One is a long-term project, which began during the summer of 1983 when a large specimen was brought to the attention of one of our wildlife biologists. The turtle was measured, weighed and marked with a few small, harmless notches on its shell before it was released. Since then 20 turtles have been marked and released. The largest weighed 128 pounds.

The second survey involved two summers of intensive trapping. Alligator snappers in this survey were also marked and released. Hired "turtle biologists" spent the entire summer trapping for alligator snapping turtles.

The traps were custom-built hoop nets made of strong twine. They are 3 feet high and 8 feet long. One end of each trap was kept closed and the other end's funnel-shaped opening allowed turtles to enter and try to get at the fresh fish bait, but the turtles couldn't get out. The top few inches of each trap was kept above the water surface so the turtles could breathe.

About 20 traps were available to be set out - depending on the size and quality of the swampy habitat. The first summer of trapping took place in 1993. Even though record flooding in 1993 made it impossible to trap for the turtles throughout much of southeast Missouri, that effort produced 23 captured turtles, marked and released where they were caught. The turtles were marked by both cutting a small groove into the edge of their shell, and by inserting a short piece of twine (tied off at both ends) into a small hole on the rear edge of the shell.

The 1994 survey resulted in 38 turtles marked and released. The combined number of turtles captured during the two years - 61 in all - may sound like a lot, but they were taken in only a few natural aquatic habitats remaining in the Bootheel.

How does someone go about setting out large traps in Bootheel swamps and streams? The young man who did the trapping in 1993 seldom got into the water and often worked alone. The second year of trapping involved a two-man team and these guys always got wet, often working in water over their heads.

They told me they found it easier to maneuver and secure the traps to a tree root or cypress knee while in the water. Of course, as they worked along the shore they always kept one eye scanning for venomous cottonmouths. Being herpetologists themselves, they enjoyed seeing these snakes, but wanted to be sure and find them by sight...not feel. Yes, the western cottonmouth is still a common species in southeast Missouri.

So far, no previously marked turtle has been trapped, which may indicate their population is larger than we thought. Most of the turtles captured during the last two years were small, young turtles (proof of a growing population) and in the future, we're hoping to learn why so few large turtles have been captured.

Also, few turtles were located in the St. Francis River where it flows along the Missouri/Arkansas state line, although the habitat seems good. This could indicate that our rare turtles have been harvested by people coming onto the river from Arkansas, where the harvest is legal.

The turtles followed in the surveys all carry a yellow or orange, numbered tag or a short piece of twine along the rear edge of their upper shell. Anyone finding or accidentally catching an alligator snapping turtle (marked or unmarked) is asked to please contact the conservation agent in the county or the nearest Missouri Department of Conservation office.

We've learned a lot about alligator snapping turtles in the past few years but we've just begun to "scratch the shell," so to speak. We

This Issue's Staff

Editor - Kathy Love
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Managing Editor - Jim Auckley
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Artist - Dave Besenger
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