This close-up photo of a Seminole bat and her two pups exhibits their furry, mammalian traits. Photo credit: Carrie Stevenson, UF IFAS Extension
As we enter Halloween season, one of the most popular images of this spooky time of year is that of a bat. The creepy tales of vampire bats and Dracula are enduring and certainly exciting. Unfortunately, many negative connotations exist around this fascinating species. Perhaps you’ve heard they carry rabies, that they will fly into your hair, or that many of them are considered blood-sucking vampire bats?
In fact, there are many benefits to having bats in one’s landscape, neighborhood, or farm. The predominant role of bats in our local ecosystems is that of insect predator. A single little brown bat (Myotis lucifugis), which is native to the Florida Panhandle, can eat 1,200 insects (including mosquitoes) in one hour of feeding! In Texas, a recent study put the economic value of bats due to their consumption of agricultural pests on cotton farms at $74/acre. Extrapolated values of bats’ pest suppression services to US agriculture is in the billions of dollars annually.
Other species in warmer climates eat fruit and play a major role in reforesting rain forests in Central and South America—after digesting the fruit they leave seeds in their droppings (guano is excellent fertilizer, by the way), helping replant 95% of the very trees they feed upon. Some species feed on nectar, filling the same role as bees and helping pollinate bananas, avocados, cashews, and figs.
Contrary to popular belief, bats are not blind and many have excellent vision. However, they do rely heavily on echolocation to sense prey and are extremely accurate hunters. Viewed close up, many people consider the small, furry animals rather cute, as opposed to frightening. They often fly erratically because they are chasing very small flying insects, so the only reason one would end up in a person’s hair is if a mosquito flew through it with a bat in chase! While vampire bats do exist, there are only 3 out of over 1,000 species of bats that feed on blood, and they all live in Latin America. They also tend to feed on the blood of livestock.
Building a bat house is a great activity for kids interested in wildlife. Photo credit: Carrie Stevenson, UF IFAS Extension
Human contact with bats is rare unless the bats are sick, which is why one found on the ground should be left alone. Rabies transmission from bats accounts for only one death per year in the United States—a statistic much less than that of deaths from dog bites, bee stings, and lighting strikes! In fact, several towns in Texas with the highest populations of bats in the country have recorded zero human bat-transmitted rabies cases.
Bat populations are declining in North America due to disease (particularly white-nose syndrome), loss of habitat, and the slow reproductive cycle of bats. However, you can help the world’s only flying mammal by installing a bat house in your yard. Keep in mind that bats attracted to bat houses prefer to be in open areas away from trees (where their predators hide), and the house should be installed at least 12 feet in the air. Bat houses can be purchased or built rather simply—this UF IFAS Extension publication outlines several types, or visit Bat Conservation International’s website for simple instructions.
When doing programs about snakes I find plenty of people who hate them… but I have never found anyone who hated turtles. I mean what is there to hate? They are slower, none of them are venomous, they have shoulders… people just like them. And to that point, when people see them crossing the road almost everyone wants to help. But that can be dangerous – for you and for the turtle. Here are couple of safety tips you should know before helping a turtle cross the road.
This small turtle can be held safely by grabbing it near the bridge area on each side. Photo: Molly O’Connor
Your Safety
You would be surprised by the number of people, particularly children, that are hit by cars while trying to help turtles cross the road. One story I heard involved nine-year-old girl who was riding in the backseat with her grandmother. They both saw the turtle trying to cross a busy highway and wanted to help. The grandmother pulled over to the side but before she could even get the car in park the little girl opened the door and ran into the highway only to be struck by an oncoming car. We all like turtles, and do not want to see them hit by cars, but as sad as it is to see a turtle hit – it is horrific to see the same happen to a child. No matter what your age – please watch for traffic before attempting to help a turtle.
Turtles Bite
Yep… unlike their reptilian cousins the snakes, lizards, and alligator, turtles do not have teeth… but they do have a beak. The beak is made of a hard bony like material that is blade sharp in carnivorous turtles, and serrated like a saw in herbivorous ones – both can do serious damage. Some species of turtles feed on a variety of shellfish, and if they can crush shell they can certainly do a number on your hand – so you have to be careful. First thing you should do is determine whether the turtle needs to be handled. If traffic is not too bad, or the road not too wide, you may be able to just manage traffic so the turtle can cross on its own. If you feel that you must handle the turtle, there are safe ways to hold them. Smaller turtles can be held safely from the sides by grabbing the bridge area – the portion of the shell connecting the top (carapace) to the bottom (plastron). Many turtles will begin to kick their feet when you do this and their claws may scratch – be prepared for this. There are two groups of turtles that have extended necks and your hands, grasped near the bridge of their shell, are still within range of their mouths – these are the snapping and softshell turtles. Both are notorious for their bites. So how do you handle those? Below is a short video put together by the Toronto Zoo that gives you some ideas on how to handle those situations.
Turtles cross highways for a variety of reasons – females looking for high dry ground to nest, individuals looking for more productive ponds, males looking for females – whatever the reason they are heading that way and will continue to do so. Placing them on the side of the highway where they came from will only initiate another attempt to cross. Move them to the side of the road they were heading.
The majority of turtle crossings occur during spring and summer. Untold numbers are killed each year on our highways – many gravid females carrying the next generation of the species. Though we encourage turtle conservation in Florida you do have to be smart about it. If you have any questions about Panhandle turtles in Florida contact your local extension office.
White Shark (Carcharhinus carcharias). Credit: Florida Sea Grant Stock Photo
From Fear to Fascination: White Sharks in the Florida Panhandle
UF/IFAS Extension – Florida Sea Grant
By Rick O’Connor (Escambia County) and L. Scott Jackson (Bay County)
Recently, I was walking on our local Gulf fishing pier checking fishing line recycle bins. You can’t walk on a Gulf pier without looking over to possibly catch a glimpse of a sea turtle or a shark, and I was not disappointed. It was hard to tell which species of shark but it was about 6 feet in length. It swam south along the edge of the pier and then east to make a large arching circle through the emerald water, past bathers at the surf break, and back to the pier only to swim the pattern again. Onlookers from out-of-town were giggling with delight to see the animal while a couple of local fishermen tried tossing bait at it, but most ignored it and went on with their fishing.
Bob Shipp’s book, Fishes of the Gulf of Mexico, lists 29 species of shark found locally. Most are members of the requiem shark family, such as blacktips and bulls, and hammerheads. Though these sharks are certainly capable of attacking humans, their presence usually does not interrupt water activities. Divers who encounter sharks may be startled at first but rarely do they end their dive or have problems with them. Even in 2005, remembered as the “summer of the shark attack”, few people stopped diving or surfing. Individuals have become educated regarding shark behavior and are not as startled when they see one. However, in 2015 there were several encounters with White Sharks.
Sightings in the Gulf of Mexico are rare but usually occur in the cooler months. Is the increased interaction with White Sharks unusual or something to worry about?
Burgess assured me that White Sharks do occur in the Gulf of Mexico usually during cooler months and are transients, as opposed to residents. Their movement in and out of the Gulf is temperature driven. As late spring Gulf waters continue to warm into early summer, sighting a White Shark is less likely to occur. According to Burgess, White Sharks use deep water when traveling but prefer shallow water when hunting fish, turtles, and marine mammals. So, inshore encounters especially in cooler months would not be unusual.
Why is there a sudden increase in the numbers of encounters?
One part of the answer lies with the increased number of White Sharks. Conservation of sharks has been effective. Additionally, with the passing of the Marine Mammal Protection Act, there are more marine mammals, thus an increase in their predators, White Sharks. The other part is the number of humans visiting the northern Gulf has increased. There are more more visitors to marine waters, especially since the Deepwater Horizon oil spill. Everyone has a camera. Beachgoers, Swimmers, Divers, and Anglers all have improved technology to record their adventures.
Is Northwest Florida a “hot spot” for White Sharks? Burgess indicated that the northern Gulf of Mexico is more productive than the peninsular Florida due to the number of nutrient rich rivers in the region. Seeing more White Sharks here would not be any more unusual than finding more snapper, lionfish, or other species of shark. As far as worrying, there have been no records of White Shark attacks in the northern Gulf of Mexico since they began keeping records in 1872.
Finally, what does one do if they encounter a White Shark?
The quick answer is nothing different than with any other shark. It is true that most White Shark attacks occur at the surface but there are no records of any attacks in Florida. Burgess indicated that the Bull Shark is probably a bigger threat than the White Shark. For more information about Bull Sharks and general tips to avoid a negative shark encounter read this articlehttps://nwdistrict.ifas.ufl.edu/nat/sharktips
In a recent video, recorded near Apalachicola, a diver was on an anchor line on a decompression stop when he saw a White Shark approaching from depth. What should a diver do in this situation? Should they swim for the surface and risk decompression sickness, remain still, or return to the bottom?
The answer has a lot to do with what the shark is actually doing. Is the shark interested in the diver or acting aggressively? Burgess suggests, you assess the situation and the shark’s behavior. All options are on the table and have to be weighed against the consequences given in this scenario. As a last resort, a diver may need to make a quick but graceful exit out of the water, past the shark, and depend on their diving partners to render aid as needed. The lesson is for divers to be prepared for a variety of potential issues on every dive.
In the final segment of this 3 part series on worms we will discuss the largest, most commonly encountered members of the worm world… the Annelids.
Neredia are one of the more common polychaete worms. Photo: University of California Berkley
Annelids differ from the other two groups of worms we have discussed in that they have segmented bodies. They are largest of the worms and the most anatomically complexed. The fluids of their coelomic cavity serve as a skeleton which supports muscle movement and increases locomotion. The annelids include marine forms called Polychaetes, the earthworms, and the leeches.
POLYCHAETES
Polychaetes are the most diverse group of annelids and most live in the marine environment. They differ from earthworms and leeches in that they have appendages called parapodia and do not possess a clitellum. In size they range from 1 mm (0.04”) to 3 m (10’) but most are around 10 cm (4”). Many species display beautiful coloration and some possess toxic spines.
There are 3 basic life forms of polychaetes; free-swimming, sedentary, and boring. The free-swimming polychaetes are found swimming in the water column, crawling across the seabed, or burrowing beneath the sediments. Some species are responsible for the “volcanoes” people see when exploring the bottom of our local bays. Most sedentary polychaetes produce tubes within which they live. Some tubes are made of elastic organic material and others are hard, stony, and calcareous. “Tubeworms” rarely leave their tubes but extend appendages from the tube to collect their food. Most feed on organic material either in the water column or on the seabed but some species collect and consume small invertebrates. There are commensal polychaetes but parasitism is rare. All polychaetes have gills and a closed circulatory system and some have a small heart. As with the other Annelids, polychaetes do have a small brain and are aware of light, touch, and smell; most species dislike light. Reproduction involves males and females who release their gametes in the water where fertilization occurs and drifting larva form.
The tube of a common tubeworm found on panhandle beaches; Diopatra. Photo: University of Michigan
EARTHWORMS
Aside from parasitic tapeworms and leeches, earthworms are one of the more commonly recognized varieties of worms. Many folks actually raise earthworms for their gardens or for fish bait; a process known as vermiculture. Earthworms differ from polychaetes in that they do not have parapodia but DO possess a clitellum, which is used in reproduction. Though most live in the upper layers of the soil there are freshwater species within this group. They are found in all soils, except those in deserts, and can number over 700 individuals / m2. The number of earthworms within the soil is dependent on several factures including the amount of organic matter, the amount of moisture, soil texture, and soil pH. Scientists are not sure why earthworms surface during heavy rains but it has been suggested that the heavy drops hitting the ground can generate vibrations similar to those of an approaching mole; a reason many think “fiddling” for worms works. Earthworms can significantly improve soil conditions by consuming soil and adding organics via their waste, or castings. Unlike polychaetes, earthworms lack gills and take in oxygen through their skin, one reason why they most live in moist soils. Another difference between them and polychaetes is in reproduction. Aquatic polychaetes can release their gametes into the water where they are fertilized but terrestrial earthworms cannot do this. Instead two worms will entangle and exchange gametes; there are no male and females in this group. The fertilized eggs are encased in a mucous cocoon secreted by the clitellum.
LEECHES
Here is another creepy worm… leeches. Leeches are segmented, and thus annelids, and like earthworms they lack the parapodia found in polychaetes and possess a clitellum for reproduction. Most leeches are quite small, 5 cm (2”) but there is one from the Amazon that reaches 30 cm (12”). Most are very colorful and mimic items within the water, such as leaves. They differ from earthworms in that they are flatter and actually lack a complete coelomic cavity; which most annelids do have. They also possess “suckers” at the head and tail ends.
The ectoparasite we all call the leech. Photo: University of Michigan
Leeches prefer calm, shallow water but are not fans low pH tannic rivers. If conditions are favorable their numbers can be quite high, as many as 10,000 / m2. They are found worldwide but are more common in the northern temperate zones of the planet; North America and Europe.
Some species feed by using an extending proboscis which they insert and remove body fluids, but most actually have jaws with teeth and use them to rip flesh to cause bleeding, cutting as frequently as 2 slices/second. Those with teeth possess an anesthesia that numbs the area where the bite occurs. Both those with and without teeth possess hirudin, which is an anticoagulant, allowing free-bleeding until the worm is full. Those who feed on blood tend to prey on vertebrates and most species are specific to a particular type of vertebrate. It is known they can detect the smell of a human and will actually swim towards one who is standing still in the water. It takes several hundred days for a leech to digest a full meal of blood and so they feed only once or twice a year. They remove most of the water from the blood once they swallow and require the assistance of bacteria in their guts to breakdown the proteins. They can detect day and night, and prefer to hide from the light. However when it is feeding time they are actually attracted to daylight to increase their chance of finding a host. Vibrations, scent, even water temperature (signaling the presence of warm blooded animals) can stimulate a leech to move towards a potential prey. Leeches, like earthworms, reproduce using a clitellum and develop a cocoon.
Though most find worms a disgusting group of creatures to be avoided, they are actually very successful animals and many species are beneficial to our environment. We hope you learned something from this series and will try and learn more.
Most people, including myself, have been taught this. Snakes are in an unusual situation of trying to kill prey with no hands or claws. A few can inject venom, others either swallow it whole (such as an egg) or the coil around their prey “suffocating” it – or so we thought. It has been my understanding that snakes did not actually “squeeze” the air out of their prey but rather coil tighter each time the prey exhales, tighten the coils until the prey is dead due to lack of oxygen. A recent paper published in the Journal of Experimental Biology is challenging this.
The issue stems around the fact of how fast the prey die. Some biologists felt death of the prey occurred to quickly for suffocation; thus began the hunt of what was the cause. Dr. Scott Boback, of Dickinson College in Pennsylvania, looked at the possibility of cardiac arrest. He and his team developed a method of monitoring cardiac and circulatory data in rats before, during, and after an attack by a constricting snake; in this study – the common boa. Using pre-attack vitals as baseline the team compared numbers during the attack and after death; which occurred, on average, 6.5 minutes. What they found was interesting.
A constricting gray rat snake coils around a bird. Photo: Nick Baldwin
Within six seconds of being bitten and having the body coil the peripheral arterial blood pressure dropped by half and the central venous blood pressure increased six fold. After 60 seconds the heart rate had dropped by 50%. After death, again mean time was 6.5 minutes, the peripheral arterial blood pressure and heart rate had dropped significantly and 91% of the rats (n=11) had evidence of a dysfunctional cardiac system. Blood samples were taken from the deceased rats. These samples indicated that the potassium levels had increased 2-fold and the pH and dropped from 7.4 to 7.0. Some suggest that the increased potassium levels may have been toxic enough to kill the rat.
Though this is only one study the results do suggest that the cause of death may be due to cardiac arrest and not the lack of oxygen. For many of us it is a point of “who cares… the rat is dead”. But for those of us in science education (teachers, park rangers, etc.) the results are of interest. We are being asked to explain how the scientific process works to students, visitors to parks, and to the general public. This is a good example of how science works. The process of experimentation finding results that do not always fit the “norm” of general understanding yet they do occur, generating more questions and more experimentation. Though this one study does not mean that suffocation is incorrect it does suggest there is another explanation and this, at least at this stage, is how we should explain such things to the public.
To view a copy of the article and abstract for this paper visit:
The elongated body of the Golden Orb Weaver. Photo: Molly O’Connor
TELL ME NO! Please tell me these huge spiders are not a part of our summer. People are afraid snakes… that’s a given – but there are just as many afraid of spiders. Honestly, after years of leading field hikes into the north Florida environment, when we encounter a spider web on the trail I have heard more screams from the boys than from the girls. But most are afraid and there nothing is more terrorizing than the huge, almost hand-size, Golden Orb Weaver (or banana spider).
The Golden Orb Weaver is one of 180 species of orb weavers from around the world; one from Australia is large enough to feed on small birds. The local species is Nephila clavipes and is found throughout the southeastern United States; in the warmer months it may reach as far north as New England. Female Orb Weavers are the really big ones you find on the webs. Their body lengths can reach 2” (not including the extended legs) and the males are much smaller at 0.02”. They have long inward pointing legs with hair-like tuffs at the joints. These are very useful in web building. They have the typical “red/yellow/black” coloration of a venomous animal and their mimics; but N. clavipes is no mimic… though mild, they do have venom. There is another orb weaver spider that is large a constructs large webs. This is the Black and Yellow Argiope (Agriope aurantia). One way to distinguish this spider from the Golden Orb is the “zig-zag” pattern it adds to its’ web near the center (where the spider spends a lot of its time).
The zig-zag pattern of the Black and Yellow Argiope spider helps to distinguish from the Golden Orb. Photo: Molly O’Connor
The name “Golden Orb” does not come from their body coloration but from the color of the silk produced for their webs. It is believed that the yellow/golden color of this silk makes it difficult for others to see in open sunny areas. Many hikers can attest to this… they are hard to see, until you become entangled… then become aware the large spider is very close and heading your way… then the scream. N. clavipes can actually adjust the hue of yellow in the silk to match the sunlight conditions where it is building its web. It is amazing to see how quickly they replace their large webs, over 3 feet in diameter, after they have been removed by people. Actually they mend and move their webs regularly. They tend to build them off ground, at eye level to the tree tops, in open areas near a line of trees. I have actually seen one build the web across a dirt road between two stands of pines as if it were going to try and capture a truck! Though species of Orb Weavers feed on small birds and snakes, N. clavipes prefers flying insects. They do not wrap their prey in silk for later feeding, as many spiders do, but rather consume them almost immediately. This may be because of a small slivery spider called Argyrodes. This spider feeds on the captured food of other spiders. N. clavipes feeding may be an adaptation to combat this kleptoparasitic spider. Another interesting behavior I have noticed is when the heavy rains come. I have noticed the web remains but the spiders leave. I am not sure where they go, most likely a hiding spot nearby, but they do leave.
The fear of spiders is most likely similar to the fear of snakes… they are venomous. Venom is used to kill prey and many times is not strong enough to kill humans, but the fact that some species can kill makes folks a bit nervous. Despite local tales that say otherwise, the venom of N. clavipes is mild. It is a neurotoxin, which can be potent, but the bite from this spider is not lethal. The typical response is pain and redness at the site of the bite, blisters may form, but it is actually less potent than a bee sting.
Like many other species of spiders, the Golden Orb Weaver is a beneficial backyard creature consuming hundreds of biting (in some cases disease carrying) insects. The large webs can be a nuisance around backyard patios and swimming pools but they can easily be moved to other locations with a rake or broom. We have many of them in our yard, one out of my office window, and enjoy watching them work. They are good panhandle neighbors.
For more information on these beneficial creatures visit:
