Our Magnificent Miner; The Gopher Tortoise
Just a decade ago, few people would have known what a gopher tortoise was and would have hard time finding one. But today, because of the protection they have been afforded by the state, they are becoming more common. This is certainly an animal you might see visiting one of our state parks.
The gopher tortoise is one of only two true land dwelling turtles in our area and is in a family all to its own. They are miners, digging large burrows that can extend up to a depth of 7 feet and a length of 15 feet underground. However, tortoises are not very good at digging up towards the surface, so there is only the one entrance in and out of the burrow. The burrow of the tortoise can be distinguished from other burrowing animals, such as armadillos, in that the bottom line of the opening is flat – a straight line – and the top is domed or arched shaped; mammalian burrows are typically round – circular. Tortoise burrows also possess a layer of dirt tossed in a delta-shaped fan out away from the entrance (called an apron). Many times the soil is from deeper in the ground and has a different color than the soil at the surface. The general rule is one burrow equals one tortoise, though this is not always true. Some burrows are, at times, shared by more than one and some may not be occupied at all. Many field biologists will multiple the number of burrows by 0.6 to get an estimate of how many tortoises there are in the area.
The tortoise itself is rather large, shell lengths reaching 15 inches. They can be distinguished from the other land dwelling turtle, the box turtle, by having a more flattened dome to the shell and large elephant like legs. The forelimbs are more muscular than the hind and possess large claws for digging the burrow. They are much larger than box turtles and do not have hinged plastrons (the shell covering the chest area) and cannot close themselves up within the shell as box turtles can. Tortoises prefer dry sandy soils in areas where it is more open and there are plenty of young plants to eat; box turtles are fans of more dense brush and wooded areas.
Tortoises spend most of the day within their burrows – which remain in the 70°F range. Usually when it is cooler, early morning or late afternoon, or during a rain event – the tortoises will emerge and feed on young plants. You can see the paths they take from their burrows on foraging trips. They feed on different types of plants during different type times of the year to obtain the specific nutrients. There are few predators who can get through the tough shell, but they do have some and so do not remain out for very long. Most people find their burrows, and not the tortoise. You can tell if the burrow has an active tortoise within by the tracks and scrap marks at the entrance. Active burrows are “clean” and not overgrown with weeds and debris. Many times, you can see the face of the tortoise at the entrance, but once they detect you – they will retreat further down. Many times a photo shot within a burrow will reveal the face of a tortoise in the picture. There is a warning here though. Over 370 species of creatures use this burrow to get out of the weather along with the tortoise – one of them is the diamondback rattlesnake. So do not stick your hand or your face into the entrance seeking a tortoise.
Most of the creatures sharing the burrow are insects but there are others such as the gopher frog and the gopher mouse. One interesting member of the burrow family is the Eastern Indigo Snake. This is the largest native snake to North America, reaching a length of eight feet, and is a beautiful iridescent black color. It is often confused with the Southern Black Racer. However, the black racer is not as long, not as large around (girth), and possess a white lower jaw instead of the red-orange colored one of the indigo. The indigo is not dangerous at all, actually it feeds on venomous snakes and it is a good one to have around.
Federal and state laws protect the indigo, as with the gopher frog and mouse. All of these animals have declined in number over the past few decades. This is primarily due to loss of the needed gopher burrows, which have declined because the tortoises have declined, and this is due to habitat loss and harvesting. Again, tortoises like dry sandy soils for digging burrows. They prefer wooded areas that are more open and allow the sun to reach the forest floor where young grasses and flowers can grow. The longleaf pine forest is historically the place to find them but they are found in coastal areas where such open wooded areas exist. The lack of prescribe burning has been a problem for them. Florida is the number one state for lightning strikes. Historically, lightning strikes would occasionally start fires, which would burn the underbrush and allow grasses to grow. In recent years, humans have suppressed such fires, for obvious reasons, and the tortoise community has suffered because of it. Therefore, we now have prescribe fire programs on most public lands in the area. This has helped to increase the number of tortoises in the area and your chance of seeing one.
All of the members of the tortoise community are still protected by state, and – in the case of the indigo snake – federal law, so you must not disturb them if seen. Photos are great and you should feel lucky to have viewed one. Though they could be found anywhere where it is high, dry, and somewhat open – the state and national parks are good places to look.
Meylan, P.A. (Ed.). 2006. Biology and Conservation of Florida Turtles. Chelonian Research Monographs No. 3, 376 pp.