Are your gators real?
If you serve on the River Patrol like Friend, & Board Member, Barbara Toeppen-Sprigg, you might get this question from visitors a lot. So Barbara decided to do the research and produced this super informative paper to help her fellow-patrollers. We thank Barbara for allowing us to share this info here so that we can all deepen our understanding of these ubiquitous Florida denizens. We guarantee you’ll never look at a gator in the same way again! Alligators are athletes very well adapted to their environment. Because they have to manage their internal temperature to optimize their ability to digest food (they are “cold-blooded”), they spend much of their time warming up and cooling down. They use the position of the sun, shade, and water to help, along with opening their mouths. They have bony prominences on their backs (osteoderms) that are filled with blood vessels to help in heat gathering and exchange. Their activity and food search will vary with the air temperature. Less than 55 degrees they really slow down, lowering their heart rate and often, when the space is available, making burrows in banks. They eat very little, and often none from November to March. Above 70 degrees, and their ability to digest picks up and so does their hunting. They are primarily carnivorous, and prefer to kill what they eat, but will scavenge dead animals when necessary. What they seek depends on their size – the hatchlings start off with insects, worms etc., while as they grow and their skills improve, they add larger prey – birds, fish, smaller alligators, deer. But they really are not big eaters! Because they do not have to spend energy, like we do, in managing the complex and energy-hogging chemical processes that keep our internal temperatures constant, they only eat about 10% of what a comparable size warm-blooded animal would eat. So, if they get a “good meal” for their size, they may not eat again for a week. They depend on surprise and superb strength – they “lurk and lunge” to catch their prey, using sense receptors on the sides of their face to detect vibration in the water as well as excellent vision and hearing. They prefer to feed from dusk to dawn, thus the warnings to avoid swimming in lakes and rivers at that time. They generally are timid, and want to escape to the water, where their excellent swimming techniques, extraordinary heart structures that maximize ability to stay underwater, and ability to use internal muscles and stones in their stomachs (gastroliths) to manage their lung capacity provide some of the reasons why this animal has survived for eons. They are also social creatures, with a variety of calls and communications. This is most evident when the males and females are “flirting” before sexual activity, when males bellow over territory, and when moms hear the “chirp” of the nestlings trying to hatch. She may carefully excavate the hatchlings and often carries them to the water in her mouth. That mom can herself open her mouth and hiss at intruders if any come close. And they are known, in a very limited way, to use tools. Alligators will manipulate a twig over their snout during nesting season for water birds to entice one to come close enough to be snatched. Fascinating animals! Here are some commonly asked questions and their answers on alligators. ACTIVITY How long can they stay underwater? They prefer short bursts of 6-10 minutes, up to 30, but the longest recorded was an animal trying to escape recapture who remained down for 6 hours. How fast can they move? They can swim up to 20 mph or on land up to 10 mph, but only in short bursts. They have surge, but not distance endurance at high speed. Where do they go when it is cold and no sun to warm them up? Their body processes slow down and if the environment allows, they will dig out dens in the banks. Do they hibernate? They can go into a half-hibernation state called brumation without feeding. Why are they only in warm waters? They can only digest their food when their body temperature rises high enough, and they can freeze in very cold environments What are those round things on their backs? They are called osteoderms, or scutes, and are bony structures filled with blood vessels that help collect warmth from the sun, which can then be circulated around the body by the blood Where are they now? They are wild animals, and travel throughout the park generally in or near the river. In cooler days they will be on the banks collecting sun, on warm days they will remain more in the water. Do they come into the head spring? Yes BEHAVIORS Will the alligators bother me? Alligators can learn to come to humans for food if they have been trained to do so. The alligators in the park are used to having humans near them, but seek their food themselves, and if you leave them alone, they will leave you alone. If you approach a nest with eggs, or a newly hatched set of babies, the mother will open her mouth and hiss at you to warn you away. Stay at least 30 feet away from any alligators you see. Is the noise I am hearing alligators? Alligators have a variety of noises, the noisiest of which is a deep bellow like thunder. It is heard most often in the mating season (May-June). The short deep sound most often heard is from a pig frog Why are they swimming across the river? Depending on the air temperature, they may change locations to get the sun or shade they need, either in or out of the water. Why are they laying in the sun? They do not have the chemical processes that keep their body temperature steady, like we do, so they use the sun and water to keep optimal inside temperatures so they can digest their food efficiently. Are they on the trails? Do they walk around on land? They can walk on land, and moms build their nests on land. They can travel on land from water source to water source. Is it safe to go canoeing/kayaking around them? They are wild animals who would rather swim away from you. Do not get close enough to frighten them. Are alligators found in salt water? Alligators do not have the salt glands that let them get rid of excess salt, so they avoid salt water generally. American crocodiles do live in salt water in South Florida. Do alligators attack under water? They eat fish and underwater birds and have a palatal flap in the back of their throat to keep water out of their breathing tubes and esophagus. To swallow, they have to return to the surface. How many alligators are there at Silver Springs? They are a wild population and can travel as they like CULTURAL Does gator meat taste like chicken?…..The flesh is said to be like pork in consistency, and taste like a combination of chicken and fish. Did they used to wrestle gators at Silver Springs? Yes, there are pictures of Ross Allen and others wrestling alligators in Florida Memory Are these (or your) alligators real?!" 😆 Yes, we do not use mechanical toys Has anyone been hurt by an alligator at Silver Springs? In recent memory the only incident was a person who was where they shouldn’t be – in the water at night. EVOLUTION Where did Alligators come from and what other species are they related to? Alligators are part of the clade called Crocodylians, and their oldest ancestors have been around 100 million years. There are three families – Crocodiles, alligators, and gharials. In the US we have both the American Alligator and the American Crocodile. The modern alligator has been around for 35 million years. Their closest animal relatives are the birds. Do we have crocodiles at Silver Springs? No. American crocodiles are only found in South Florida FEEDING What do they eat? Depends on their size. Nestlings start with insects, worms, shrimps, snails and as they grow and develop skills, they can add fish, birds, rodents, otter, turtles, frogs, smaller alligators, deer When do they eat? When temperatures are below 65-70 degrees they don’t eat. As temperatures rise, they generally feed between dusk and dawn Do they eat in the winter? No. Low temperatures make digestion very difficult What do they do if they catch something that is too big to swallow? They toss it around, trying to separate parts, and will tear off pieces Do big alligators eat little alligators? Yes, they can be cannibalistic Would a gator eat my little dog? If you let the dog off leash near a river at dusk and it went to investigate the shore, it could be caught by an alligator. They are lurkers, not hunters Will gators attack or eat a manatee? Adult manatees are very large, and very protective of their young, so make difficult targets. There have been instances of manatees found with flipper marks from alligators, and carcasses can be scavenged. Do they eat a lot of food? No. Alligators can go up to two years without food, and generally they eat once a week. What is average weight of a gator? They can weigh up to a ton, but the average male is 500 to 600 pounds How big can the alligators get?…..Females will be 6-8 feet long, males 12-14 feet. Males at maturity are larger than females. Florida record is 14 ft 3.5 inches. Heaviest was in Alachua County at 1043 pounds How big are the alligators at Silver Springs? We haven’t measured them. There is no current research project involving alligators in the Silver Springs State Park INTELLIGENCE Is their brain really the size of a walnut?…..Their brain has the same segments we do – forebrain, midbrain and hindbrain. The forebrain has the lobes for smell and the cerebral hemispheres, are comparatively larger than other reptiles, but much smaller than in mammals or birds. It is very small – about 0.004% of body weight, about the size of your thumb, in a mature adult alligator. Do they use tools?…..Alligators have been photographed manipulating twigs on top of their snouts to entice a nest-building bird to come pick it up, where the bird can be snatched for dinner LIFESPAN How do you tell the age of a gator? There is no present way to tell the age How long do they live? Generally, 30-50 years. The oldest in captivity was born before 1936 so is more than eighty years old, having survived World War II in Belgrade, Yugoslavia.
REPRODUCTION How many eggs does a mother carry and how many survive? An average or 35, of which 4 are likely to survive to maturity What determines the sex of the babies? Alligators have no sex chromosomes. They have temperature dependent sex determination. Generally, if portions of the nest temperatures are less than 88 degrees or more than 93 degrees females will be produced, and between 88 and 93 degrees males will be produced. Sections of the nest differ in temperature. How long does it take for the alligator eggs to hatch? 60-65 days. In central Florida they hatch early to late September. When the babies start to make their way out of the egg, they chirp, which brings mom to help. Moms may take the egg between their teeth and gently roll it around to help the hatchling out. She may carry them to the water in her mouth, and moms have been seen holding meat in their mouths for the nestlings to pull chunks off. How long is the mother protective of her young? It varies from a few days to several years, but the general period is one year. Do the parent alligators take care of the babies and if so for how long? The alligators and their relatives, the crocodiles and gharials, are the only reptiles to show substantial maternal care. Some males participate in some groups. How long do the yellow stripes on a gator last? Generally, four years Can you tell the difference between a male and female alligator? Only by turning it over on its back and opening its genital slit. This is not recommended. YEARLY CYCLE - November – March – very little feeding, mostly brumating - May-June – Mating, lots of growls - Late June- early July – nests made, eggs incubate - Early to late Sept - Hatchlings emerge, chirping to alert Mom& Dad Hatchlings – first year Yearlings – second year Juvenile SOURCES: Grigg & Kirshner, Biology and Evolution of Crocodylians, Comstock Publishing Associates:2015 Florida Fish and Wildlife Conservation Commission, American Alligator, https://myfwc.com/wildlifehabitats/profiles/reptiles/alligator 5/1/19 IFAS Extension, University of Florida Swiman, Hoestetler, Webb, Miller, Main “Living with Alligators: A Florida Reality” document WEC203 rev April 2017 www.crocodilians.com, hosted by the University of Bristol and the Florida Museum of Natural History
Author: Barbara Toeppen-Sprigg 5/25/19 |
