Vacation 2022 Part 1–Jekyll Island

May 20, 2022

We were pleased with our room in the Days Inn at Jekyll Island. Many hotels claim to be handicapped friendly, but it seems as if they pay perfunctory attention to the needs of disabled people. However, this hotel really had excellent handicapped facilities, making my wife happy, thus reducing my stress, so I could enjoy the beach.

Driftwood Beach

An interesting active geological action is currently taking place on Jekyll Island. Engineers dredge the river outlet north of the island, and along with natural currents, this is causing the north end of the island to rapidly erode. The ocean is inundating a maritime forest here, killing the live oaks and cedar trees where they stand. This landscape is beautiful and different. Jekyll Island is not shrinking away. Longshore currents carry the eroded sediment from the north end of the island to the south end, and this end of the island is expanding in the form of large sand dunes.

The ocean is inundating the northern end of Jekyll Island, killing the maritime forest that stood here for centuries.
One can see how extensive a live oak’s root system is.
Bye bye forest, hello ocean.
Sediment from the north end of the island is carried by longshore currents to the south end of the island where it forms large sand dunes.

Sharktooth Beach

I’d rename this broken shell beach. Although I’m sure people find shark teeth here, they are greatly outnumbered by broken seashells. The beach appears to be composed of modern shells mixed with black-colored fossil specimens. It took us about 15-20 minutes to walk from the road to this beach located on Jekyll Creek between the island and the mainland. Many cedar trees covered in grapevines grew alongside the trail, and a salt marsh was also adjacent.

Sharktooth beach. We didn’t find any definitive shark’s teeth here.
Oyster shell, sea drill, and some other broken shells I found on Sharktooth Beach. The darker ones may be fossils.

The Sea Turtle Center

Veterinarians treat injured sea turtles here. Most are injured by human activities. It is worth the visit, but I felt sad the only opportunity to see these poor creatures is when they get hurt.

Loggerhead sea turtle being cared for at the Sea Turtle Center on Jekyll Island.
Juvenile loggerhead sea turtle.
Sinkey Boone, a shrimp trawler captain, invented the sea turtle excluder which are now required equipment on all shrimp trawlers. They let in shrimp but prevent turtles from getting caught in the nets and drowned. Sinkey seems like a bad name for a boat captain.
Diamondback terrapin juveniles. The Sea Turtle Center also cares for this species and injured box turtles as well.

Birds on Jekyll Island

I saw 19 species of birds on Jekyll Island plus gray squirrels, and the tracks of rabbit, deer, and raccoon on the beach.

Female boat-tailed grackle. This species is by far the most common songbird on the island. Males are larger and pure black.
Piping plover. This species spends summers in high northern latitudes. It still has a long way to go.
I think these are semi-palmated sandpipers.
I cannot identify what species of sandpiper this is. Closest match I can find is a sanderling. Somebody help.
This was part of a huge flock of brown pelicans.
Even Bugs Bunny likes to go to the beach. These are rabbit tracks.

My bird checklist for Jekyll Island includes boat-tailed grackle, red-winged blackbird, mourning dove, bluebird, cardinal, tufted titmouse, green heron, snowy egret, laughing gull, ringed gull, piping plover, semi-palmated sandpiper (I think), sanderling (I think), immature white ibis, common crow, fish crow, black vulture, black skimmer, and brown pelican. I also saw gray squirrels, a road-killed black racer, and the tracks of rabbit, raccoon, and deer.

2 Miocene-Aged Fossil Sites in Florida

May 11, 2022

The University of Florida Museum list 9 Miocene-aged fossil sites in Florida. By contrast there are no significant Miocene-aged fossil sites in Georgia. However, animals that lived in Florida also occurred in Georgia because the same habitats–subtropical forests and woodlands–prevailed over most of North America during the Miocene era, a period of stable warm climate. The Miocene lasted a long time from 25 million years BP-5 million years BP, but this division of time is an artificial human construct. Species that lived during the early Miocene were completely different, though often ancestral, to those that lived in the later Miocene. Therefore, I chose to examine the lists of Miocene species that occurred at 2 different sites with fossils separated in age by over 10 million years. Both sites are located northwest of Gainesville, Florida and are about an hour drive from the Georgia border. Certainly, these species lived in Georgia as well.

Fossils from the Thomas Farm site are estimated to be 18 million years old or early Miocene. The site was discovered in 1931 when Raeford Thomas dug a well into an ancient sinkhole. Clarence Simpson of the Florida Geological Society looked through the dirt dug up from the well-drilling and was the first to catalogue fossils at the site. The site has been studied off and on ever since, and scientists consider it the best North American Miocene-aged site east of the Mississippi. Paleontologists list 1 species of fish, 12 species of amphibians, 23 species of reptiles, over 27 species of birds, and 40 species of mammals from the fossil evidence left here. Most notable among the reptile fossils are an extinct boa constrictor (Boa barbouri), and an extinct alligator (Alligator olseni). Boa constrictors are now restricted to southwestern North America south to South America, but they were widespread across North America during the warmer Miocene. Olsen’s alligator was somewhat smaller than modern alligators. None of the bird fossils found here have been diagnosed to the species or even genus level. Scientists are unfamiliar with birds from this era, and they can only diagnose the specimens down to the family level. The most common large vertebrate fossils found here are from 3-toed horses and rhinos both of which dominate Miocene fossil assemblages. A common species of horse of this era was the 60-pound Archaeohippus blackbergi. Many of the specimens suggest high mortality caused by intraspecific fights between males who sported long canines. Thomas Farm is the only site where bones of an extinct camel known as Floridatriculus dolochiantereus have been found. Extinct species of pronghorns also left fossil evidence in the sinkhole. The top predator was White’s bear-dog (Amphicyon whitei). It was related to the common ancestor of bears and dogs, and it grew to the size of a grizzly bear.

This 60 pound 3-toed horse was a common species in early Miocene forests. 3-toed horses occupied an ecological niche filled by white-tailed deer today.
Bear-dogs were a top predator during the early Miocene. White’s bear-dog grew to the size of a grizzly. They were related to the common ancestors of bears and dogs.
Extinct species of pronghorns ranged throughout southeastern North America during the Miocene. Today, there is just 1 species restricted to short grass prairies in some western states.

Farmers plowing a peanut field discovered Miocene-aged fossils at the Tyner Farm site. This site was excavated between 2001-2005, and fossils from this site are estimated to be 7.5 million years old. Paleontologists list 4 species of amphibians, 6 species of reptiles including 2 kinds of giant tortoise and the remains of the modern species of alligator (A. mississippiensis), and 25 species of mammals. The site yields the oldest dated fossil remains of a tree squirrel in North America. Like the older dated Thomas Farm site, the fossil assemblage is dominated by 3-toed horses and rhinos, though they are different species than those found at the older site. Bones of 4 species of horse, 2 species of rhino, 2 species of pronghorn, 3 species of camels, 1 species of tapir, and 1 species of peccary were found here. 1 species of camel is particularly remarkable–Aepycamelos major. It was 13 feet tall, not counting its 6-foot-long neck, and it weighed over a ton. This species is a good example of convergent evolution. Like giraffes, it evolved great height and a long neck to feed upon leaves and twigs other vertebrate herbivores couldn’t reach, and scientists refer to them as giraffe-camels. Top predators included the Borophagine or bone-eating dogs, and the saber-toothed cat (Machaerodes catcopsis). The latter species was likely ancestral to the more famous late Pleistocene species of saber-tooth cats.

This is the hippo-like rhino. Along with 3-toed horses, rhinos were the most common large herbivores during the late Miocene. Rhinos became extinct in North America at the end of the Miocene when Ice Ages began.
The amazing giraffe-camels are a great example of convergent evolution. Despite not being closely related to giraffes, they evolved long necks to help them reach the leaves at the top of trees they could eat.

Pleistocene North America is often compared to modern day Africa in its faunal diversity. However, as I’ve noted in a previous blog entry (See: https://markgelbart.wordpress.com/2013/12/09/the-faunal-diversity-of-pleistocene-north-america-was-less-than-that-of-modern-day-africa/ ), modern Africa far exceeds Pleistocene North America in number of genera and species. Miocene North America makes a better comparison in diversity because a far greater number of animal species occurred on the continent during this era. Ice Ages began occurring at the beginning of the Pliocene about 5 million years ago. Seasonal climates including sub-freezing weather severely reduced the number of species that could live in North America.

Reference:

https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/sites/

A Lake and 2 Rivers in Florida that Vanish

May 4, 2022

The Native-American name for Lake Jackson, located near Tallahassee, Florida, is Lake Okeeheebee, meaning disappearing waters. Local authorities should have kept the original name because there is another Lake Jackson in central Florida, and there is also a Lake Jackson in nearby Georgia. The existence of multiple Lake Jacksons in this region made researching this blog article confusing. I wonder what Native-Americans thought the reason was for the periodic draining of this lake. They probably invented some kind of mythical story. Modern geologists know the cause for the periodic disappearance of this lake. The lake sits on karst terrain where sandy soils prevail. Karst terrain consists of unevenly eroding limestone. Slightly acidic rain causes bedrock to erode, resulting in many underground caverns that often collapse into sinkholes. There are 2 sinkholes underneath Lake Jackson–the Porthole Sink and the Lime Sink. During dry spells when the water table falls, water from Lake Jackson drains into these sinkholes, just like water draining from a bathtub. Plant debris and mud will temporarily block the sinkholes, but eventually most of the lake will drain with the exception of small pools here and there where fish populations survive. The permeable sandy soils allow water to refill the lake following periods of higher rainfall that cause the local water table to rise.

Map and location of Lake Jackson in north Florida. From Wikipedia.
Lake Jackson when it is full of water.
Aerial photograph of Lake Jackson after its water vanishes. Lake Jackson is surrounded by wet prairie. From the Tallahassee Democrat by Daniel Martinko.

Lake Jackson is 6.2 square miles and averages 6 feet deep when it is full of water, though it is as much as 28 feet deep over the sinkholes. The lake has drained 14 times over the past 200 years, and it is currently in a drained stage. Surprisingly, periodic drainages are good for fishing. The draining reduces populations of the non-native plant hydrilla, and the re-filling stirs up nutrients, increasing food for rebounding fish numbers. Fishermen claim the fishing for largemouth bass, crappie, bluegill and redear sunfish, and bullhead catfish is excellent. The latter species is especially well-adapted for surviving in small pools during drainage phases. Though not mentioned on the internet, I’m sure bowfin, gar, and non-native tilapia thrive as well. Birdwatchers report the presence of herons, egrets, limpkins, eagles, ospreys, ducks, geese, fish crows, and least terns. It’s good habitat for alligators, turtles, and frogs too.

The karst terrain makes it difficult for rivers to flow in this region, and there are 2 rivers that vanish here. The Alapaha River, a tributary of the Suwannee River, simply disappears into the ground, flowing right into a sinkhole, and it emerges miles away. The Santa Fe River also disappears into a sinkhole, also to emerge miles away. Both become subterranean during part of their course. A river flowing into the ground is known as a swallet.

Photo of the Alapaha River where it vanishes into the ground. It re-emerges miles away.
Image of where the Santa Fe River vanishes. From a youtube video by Adlai, JN.

Reference:

Bryan, J., Scott, T., Means, Guy

Roadside Geology of Florida

Mountain Press Publishing Company 2008

When South Georgia was Deep Under Ocean Currents

April 27, 2022

An Atlantic Ocean shoreline occurred at the present-day location of the Georgia fall line along an axis from Augusta to Macon to Columbus. Immediately offshore the ocean was shallow, but farther off the coast ocean currents were strong and flowed over a deep channel. This channel originated from a suture or fault where part of the African continent formerly connected to North America before the supercontinent of Pangaea rifted apart. Following sea level rise, ocean currents began flowing over this natural low area about 99 million years ago. Geologists refer to it as the Suwannee Strait during the first 60 million years of its existence and the Gulf Trough from the mid-Eocene to the mid-Miocene. Sea level changes caused the low channel to shift to the northwest, hence the name change. The swift current that flowed over it was part of the clockwise-moving Gulf Stream, an ocean circulation pattern found all the way up the North American east coast. To the south of the Suwannee Strait/Gulf Trough were shallower seas dotted with coral reef islands. During the Oligocene a large island, known as Orange Island, though no oranges grew there yet, emerged above sea level south of the trough. The Gulf Trough was deepest during the late Eocene about 35 million years ago, and geologists think parts of it were 600 feet underwater. During the Miocene sediment washed down from eroding Appalachian Mountains began to fill in the Gulf Trough. In its later years of existence, it was a slow-moving narrower estuary. About 15 million years ago sea level fell and the Gulf Trough existed for a while as an above ground canyon. Today, this canyon is buried deep underneath millions of years of sediment, but there are exposed outcrops where rivers erode through this ancient sediment. However, a relic is visible underwater in the Gulf of Mexico, and it is known as Desoto canyon.

From 99 million years ago to 15 million years ago South Georgia was under deep ocean currents. Geologists refer to this area as the Suwannee Straight and the Gulf Trough. It reached its largest depth about 35 million years ago. The Atlantic Ocean shoreline occurred along the present day fall line. South of this trough was a shallower sea dotted with coral atolls and islands that periodically rose and sank according to changing sea levels.

Swift ocean currents carried well oxygenated sea water that supported abundant aquatic life in the Suwannee Strait during the Cretaceous. Monstrous mosasaurs and pliosaurs preyed upon bony fish, some species themselves armed with fangs. Sea turtles and sharks swam over beds of an extinct group of clams known as rudists that came in many different shapes and sizes. Ammonites, extinct cephalopods related to squids and octopi, thrived in Cretaceous seas. Today, most foraminifera are small and measured in millimeters, but oddly enough there were 4-inch-long species of foraminifera living in the Suwannee Strait, though they are one-celled animals related to amoeba.

Rudist clams were abundant in the Suwannee Strait during the Cretaceous era. They came in many different shapes. They went extinct along with the dinosaurs at the end of the Cretaceous.

During the Eocene primitive whales evolved and made the Suwannee Strait their home. The Suwannee Strait and later the Gulf Trough was still rich in fish, mollusks, and other sea life. Fossils in the limestone and shale deposits of Cretaceous through Miocene Age in the region are commonly found wherever erosional processes expose them, and the limestone itself is made of many ancient seashells.

Primitive whales swam alongside dugongs, sharks, bony fish, and turtles in the Gulf Trough during the Eocene. A skeleton of this species was found in Burke County, Georgia.

Notable fossils of Oligocene Age from the Gulf Trough include dugong, nautilus, and rhodoliths. A nearly complete skeleton of a dugong was found in a northwest Florida fuller’s earth mine. Today, just 3 species of nautilus are extant, and these occur in the Pacific and Indian Oceans, but apparently, they were common during the Oligocene in the Gulf Trough. Aturia alabamensis, a 2-foot-long nautilus, likely scavenged or actively hunted crustaceans on the sea bottom. Rhodoliths still exist but were especially abundant in the Gulf Trough during the Oligocene. Rhodoliths are species of red algae that resemble coral and also produce calcium carbonate. Rhodolith fossils are part of large fossiliferous limestone outcrops found in southwest Georgia and are thought to have occurred on the shallower flanks of the Gulf Trough.

Aturia alabamensis. This was a species of nautilus that grew to 2 feet long and was common in the Gulf Trough during the Oligocene.
Rhodoliths, red algae that resembles coral, was abundant in the Gulf Trough during the Oligocene. They are still extant.
DeSoto Canyon off the Florida coast is the only remnant of the Gulf Trough that hasn’t filled with sediment.

John J. Audubon’s Trip Down the Ohio and Mississippi Rivers During 1820/1821

April 20, 2022

It’s hard to imagine how rich in wildlife the woods, fields, and streams of North America used to be. This is why I enjoy reading the journals of early explorers and settlers who described these forlorn scenes of nature. They saw more wildlife in a day than most modern people see in a year both in numbers and diversity. Audubon kept a journal of his trip down the Ohio and Mississippi Rivers, a journey that lasted from October 12, 1820 to January 7, 1821, and it is an extensive account, documenting the former abundance of wildlife in the region. Audubon had suffered business reversals when his once prosperous store went bankrupt, and he decided to travel to New Orleans where he could make money by drawing portraits of rich people and by giving art lessons. He was also working on an illustrated book of birds he hoped to sell in England. He left his family in Cincinnati, and he expected to be gone for 7 months. He traveled on a flat boat with an 18 year old young man, a boat captain, and a hunting dog named Dash that he alternatively referred to as “the bitch” or “the slut.”

J.J. Audubon and his dog. Although his name is attached to a modern conservation society, he killed as many birds as he could shoot.

Audubon and his young companion stopped to hunt every morning. Audubon carried a primitive shotgun known then as a fowling piece, and he shot just about every animal he saw. Unlike the organization that today uses his name, Audubon was not at all concerned about conservation. In his later years he did lament the reduction in game populations, but then he’d kill as many birds as he could shoot. A typical day of his journey was the first when he and his companion killed 30 “partridges” (probably quail), 27 squirrels, 1 woodcock, 1 barn owl, and 1 turkey vulture. After the morning hunt, he would draw 1 of the dead birds as the boat drifted downstream. Then he would pluck and clean the bird and throw it on the embers of the fire for his supper. Grebes were fishy, but he pronounced red-breasted thrushes (robins) to be fat and delicious. Birds that are now extinct were common during the early 19th century. Audubon often saw ivory-billed woodpeckers, and he stated they were more abundant along some parts of the river than pileated woodpeckers and flickers. He once shot 10 Carolina parakeets and fed them to his dog to see if they were poisonous. This seems strange, but Audubon often engaged in sadistic “scientific” experiments. He wrongly came to the conclusion parakeets were not poisonous when his dog didn’t get sick. He didn’t know the flesh of parakeets only became poisonous after they ate certain species of toxic plants. Audubon also wrongly thought immature bald eagles were a different species of eagle, and in another sadistic experiment he once nailed the foot of an eagle to the bottom of the boat, so he could draw it while it was alive. He claimed bald eagles were a new species and named it the bird of Washington after the first President.

Alexander’s painting of a bald eagle (top) and Audubon’s painting of a bald eagle (below). Some think Audubon simply plagiarized Alexander’s painting and falsely claimed his was based on a freshly killed eagle.

Species of birds still extant today were much more abundant and widespread during Audubon’s time. He saw a flock of 100 white pelicans on a sandbar in the Ohio River. White pelicans are not often seen on the Ohio River today. He also saw enormous flocks of thousands of ducks, geese, and blackbirds. Swans, herons, and sandhill cranes were a common sight. In addition to daily hunting, Audubon always set a line out for fish. On 1 occasion he caught a 64-pound catfish, likely a blue catfish–a new species for him. I’m sure the offal from all the birds he killed made excellent catfish bait. Big flocks of sea gulls followed the boat and fed upon the dead bird and fish parts he threw overboard. Once, his hunting led to fish and bird…he shot a merganser with a 9-inch-long sucker fish in its throat. Nearly extinct habitats were abundant then as well. They floated down parts of the river bordered by many miles of bamboo cane tangled with smilax vines. Canebrakes are very rare today.

Audubon saw a flock of 100 white pelicans on a sandbar in the Ohio River. According to range maps, this species no longer regularly occurs on the Ohio River.

Audubon reached New Orleans on January 7th. Gulls, fish crows, and robins were the most common winter birds here. Later in the season, the robins left, but tree swallows arrived to become 1 of the most common birds around the city. On his 2nd day in New Orleans, someone picked his pocket, but he was almost broke anyway. He made his living painting people’s portraits and giving art lessons. A notable incident while he was living in New Orleans was when he witnessed local hunters destroy a flock of 144,000 migrating golden plovers. Eventually, Audubon got a job tutoring the daughter of a rich plantation owner. (Audubon was unapologetically pro-slavery.) He taught her art, dancing, and math for $60 a month plus room and board. The plantation was located on Bayou Sara, and Audubon hunted daily in a nearby cypress swamp where he frequently saw prothonotary warblers, yellow-throated warblers, water thrushes, Mississippi kites, ivory-billed woodpeckers, and alligators. The women in the household where he tutored gradually cooled to him, and he quit. I wonder if they were expecting more romance from the married tutor. The lady of the house didn’t want to pay him, but the man did anyway. The private journal ends when Audubon returns to New Orleans, following his tutoring gig. Years later, Audubon did become successful selling his illustrated books about North American birds and mammals.

References:

Audubon, J.J.

Audubon: Writings and Drawings

Literary Classics 1999

Halley, M.

“Audubon’s Bird of Washington: Unravelling the Fraud that Launched The Birds of America

Bulletin of the British Ornithologists Club 110-141 2020

Trichinella sp.

April 12, 2022

My late father was a physician fresh out of medical school when he encountered a patient with symptoms that baffled his more experienced colleagues. The patient suffered from fever, nausea, diarrhea, fatigue, muscle soreness, headache, stomachache, and eye swelling. None of the older doctors could diagnose his ailment, and the young teenager appeared to be on the verge of death. In desperation they consulted with my father, and he recognized the symptoms of trichinosis, a parasite infection caused by roundworms in the trichinella genus. At first the teenager denied eating undercooked pork, but then he admitted to tasting uncooked pork sausage. He was treated with life-saving anti-parasite medications. The boy’s father happened to be a gangster who worked for the mafia, and after this incident my dad liked to brag the mafia would get him anything he wanted in gratitude. My dad also liked to think his help influenced the boy not to follow in his father’s footsteps. Instead of becoming a gangster, he chose dentistry as his profession.

Lifecycle of a trichinella round worm parasite. Image from the CDC.
Image of trichinella cysts in human muscle tissue. From a medical encyclopedia.

Carnivores, humans, pigs, and rodents spread trichinella worms when they consume meat infested with roundworm cysts. Digestive juices in the small intestine activate the cysts, freeing the roundworms from encasement within the cyst. The parasites pierce the lining of the small intestine and enter the blood stream where they burrow into muscles, mate, and lay eggs that become cysts, waiting to get eaten. How sick an animal gets depends on how many cysts are ingested and how strong the animal’s immune system is. An ingestion of highly infested meat can be fatal because the trichinella worms will also burrow into heart, lungs, brain, and eye tissues. Doctors diagnose trichinosis by taking a muscle biopsy and exposing it to digestive juices. If roundworms are activated, the patient is considered to have trichinosis. Patients are treated with anti-parasite medications including mehendozole or albendozole.

Trichinella is supposedly absent from pork raised in the U.S. and western Europe because modern pigs are fed a clean grain-based diet and are kept in sanitary cages where they don’t have the opportunity to eat dead rats. This hasn’t always been the case. During the middle of the 20th century, trichinella was widespread among domesticated pigs. One study in 1947 of 5000 people found trichinella roundworms in 16.1% of the population. The infestation rate was particularly high in New York City during the 1930s because New Jersey pigs were fed restaurant garbage with trichinella-infested meat and rats. An average of 400 cases of trichinosis were diagnosed every year during the middle of the 20th century, and this figure is likely an undercount because trichinosis symptoms mimic flu symptoms. Many people with trichinosis probably thought they had the flu. As late as the 1960s, 2.2% of Americans had trichinella parasites in their bodies.

New cases of trichinosis in the U.S. average about 20 a year now, and these are from hunters who consume undercooked wild boar or bear. The CDC recommends cooking meat to an internal temperature of 180 degrees F to kill trichinella, though other sources say temperatures as low as 120 degrees F are adequate. Freezing meat at 5 degrees F for 10 days will kill Trichinella spiralis, but freezing does not kill other species of trichinella, and these species are more likely to be found in wild game.

I ate wild boar last week. Sprouts Market sells Durham Ranch products, and this company sources wild boar from Texas. I made wild boar papardelle–a dish reportedly popular in the Tuscan region of Italy. To make wild boar papardelle, marinate 1 lb of ground or finely chopped wild boar in 1 cup of Burgundy and 1 TBL of rosemary overnight. Put a carrot, onion, and chopped garlic in a food processor and grind them up. Remove the meat from the marinade and brown it in an electric skillet, while sautéing the chopped vegetables. Mix the vegetables with the meat and add the marinade and a 6 ounce can of tomato paste. Let this simmer, then add cooked egg noodles. In Tuscany parmesan cheese is not added, but my wife and daughter wanted it on their servings. The meat tastes of wine and tomato paste, and any meat would probably taste the same with this recipe.

Wild boar should be cooked thoroughly. Unlike pigs raised in modern sanitary conditions, wild boar can ingest trichinella parasites.
Wild boar papardelle is reportedly a popular dish in the Tuscany region of Italy. It’s easy to make.

Pleistocene Caracaras

April 6, 2022

The pasturelands interspersed with woodlots that cover much of rural south Florida today likely resemble the coastal oak and pine savannahs of this same region during the Pleistocene. South Florida and the southern Gulf Coast were climatically out of sync with the rest of North America during Ice Ages. When climate phases of dry cold conditions struck the rest of North America, south Florida and the southern Gulf Coast experienced warmer wetter subtropical climates. The Gulf Stream of the present day carries tropically heated water north, keeping climates in the northern latitudes of North America relatively moderate, but during cold climate phases of the Ice Age, it shut down. Instead, this warm water stayed at lower latitudes ironically making climate along the southern Gulf Coast even warmer than present day conditions. This warm climate spurred frequent thunderstorms and hurricanes. Lightning-ignited fires and windstorms destroyed trees and created open savannahs where mammoths, bison, and horses further suppressed the growth of unbroken forests. Trees that survived fire and wind were spaced far apart, and woodlots were restricted to the vicinity of waterholes where the trees were protected by watery fire breaks. This warm savannah habitat occurred from south Florida, Alabama, Mississippi, Louisiana, and Texas all the way to eastern Mexico. Much of this land has been inundated by sea level rise since the end of the last Ice Age. Warm coastal savannahs were ideal habitat for many species of plants and animals including caracaras.

Crested caracara. Photo by Wisniewski.
Crested caracara range map. There is a disjunct population in south Florida. During the Pleistocene this range was continuous with its population in Central and South America. Warm savannah occurred along the Gulf Coast, much of which is now inundated by rising sea levels.

Two species of caracaras inhabited Gulf Coast savannahs during the last Ice age–the crested caracara (Polyborus plancus) and the yellow-headed caracara (Milvago reidei). The former still occurs as a relict population in south Florida. This species lived on dry prairies throughout much of Florida, but that type of habitat has largely been transformed to rural, suburban, and urban landscapes. A recent scientific study in Florida found 103 crested caracara nests, and most of those were on improved pastureland. They seem to prefer pastureland over what remains of their original dry prairie habitat. I think this is a clue they benefit from the presence of megafauna. During the present day this means herds of cattle, but formerly they accompanied now extinct and extirpated megafauna. Caracaras forage on the ground for carrion. There was an abundance of carrion during the Pleistocene. They hunt for insects, reptiles, and small mammals stirred up by grazing herds of megafauna. And along with swallow-tailed kites and other opportunistic birds, they hunt down small animals fleeing wildfires. The widely spaced trees and small woodlots located on the pastures or savannahs are used for nesting.

Study of crested caracara nests in south Florida. Most of their nests are located on cow pastures that resemble Pleistocene habitat. Image from the below reference.
Yellow-headed caracara.
Yellow-headed caracara range map. During the Pleistocene they also occurred in Florida.

Fossil remains of both species were found at the Cutler Hammock site located in Miami, Florida. Yellow-headed caracaras no longer occur in North America, but habitat during some phases of Ice Age climate was so favorable in this region that it attracted both species. The Cutler Hammock site is notable for having yielded many remains of large carnivores including dire wolf, saber-tooth, giant lion, jaguar, and cougar. Their kills helped feed a diverse population of avian scavengers.

Reference:

Morrison Joan

“The Crested Caracara in the Changing Grasslands of Florida”

Click to access 3-17145_p.21115_Mor_FDPC_d.pdf

See also: https://markgelbart.wordpress.com/2013/10/18/two-pleistocene-carnivore-dens-near-miami-florida-part-2/

Pigloos

March 30, 2022

Wild boars (Sus scrofa) are an amazing adaptable Pleistocene survivor. Their fierce disposition and large litter sizes enabled them to survive predation from wolves, lions, and humans during the Pleistocene, and even today modern human hunters, sometimes armed with machine guns, have trouble putting a dent in their populations. They eat just about anything, and they can live in most climates. Wild boar remains, dating to the Pleistocene, have been found in at least 109 fossil sites located in Israel, Morocco, Libya, Greece, Monaco, Italy, France, Spain, Portugal, Germany, Austria, the United Kingdom, Slovakia, the Czeck Republic, Russia, China, Vietnam, and Indonesia. Some populations of wild boar were domesticated 5,000 years ago, and their descendants are modern day pigs–source of the pork chops, ribs, and bacon stocked by supermarkets. European settlers brought pigs to the Americas 500 years ago and let them forage in the woods where many escaped and went wild. 100 years ago, hunters introduced wild boars to the Appalachians, and they promptly interbred with existing wild pig populations, creating a kind of super hog that game managers have difficulty controlling. Pure bred wild boars wouldn’t be unmanageable, but domesticated pigs have been bred to produce exceptionally large litters, and the combination of tough wild boar with pigs that produce super-sized litters has overwhelmed many areas.

Wild boars have been abundant for over a million years.

Hunters recently introduced wild boars to Canada, resulting in the same situation found in parts of the U.S. and South America. Their ability to adapt to frigid Canadian climates surprised researchers. During winter these intelligent animals build houses constructed of cattail reeds near marshes. Snow and ice cover the houses, giving them the appearance of an igloo, and accordingly they are called pigloos. The pigs burrow into their pigloos, and the reeds covered in snow insulate the pigs and help keep their body heat inside the structures. Canadians need to increase the wolf population, so they can huff and puff and blow the pig houses down. Unfortunately, this would face too much opposition from hunters and ranchers.

Wild boars are spreading throughout Canada. They can live in colder climates because they build nests out of cattail plants known as pigloos. The well insulated nests are kept warm by the beast’s own body heat.

Cretaceous Age Fossil Feathers Found in Alabama

March 23, 2022

More fossil feathers of Cretaceous Age have been found in the state of Alabama than in any other state. 14 fossil feathers, encased in shale, were found in a lens located in the Eutaw Formation, the site of an ancient shoreline. Shale is basically fossilized mud, and ocean currents rapidly buried the feathers in mud which eventually turned to shale. The fossilized feathers are impressions of the original objects. The Cretaceous Age lasted from 145 million years BP to 66 million years BP, and these feathers probably date to about 80 million years ago. Fossilized feathers have also been found in Kansas, New Jersey, New Mexico, and Alberta; but none of these states or provinces have yielded as many as Alabama.

Fossil feathers found in Alabama. The impressions were made in mud and later fossilized when the mud turned to shale. Photo from the below reference.

The feathers include 2 different sizes. Scientists believe the smaller ones come from extinct species of shorebirds. The larger feathers may be from the tails of either a species of hesperornthid or a dromaeosaur. Hesperornthids were an aquatic fish-eating dinosaur that occupied a niche similar to modern day penguins. They were related to the ancestors of birds, and they lived in lakes, rivers, and oceans. Dromaeosaurs include dozens of families of carnivorous dinosaurs ranging in size from 2 feet long to 20 feet long. Some species hunted in packs, though paleontologists are unsure whether they were organized hunters or disorganized mobs like modern Komodo dragons and crocodilians. Some species had a large retractable claw on their 2nd toe that could inflict devastating damage on their prey or each other. Carnivorous dinosaurs were cannibalistic, and the number of carnivorous predators in ratio to herbivorous prey was higher than in modern day ecosystems. For example today in a pristine environment there may be 1 large predator per 40 deer, but during the Cretaceous there may have been 1 predator per 5 large herbivores. Dromaeosaurids were related to the ancestors of birds, and some species may be directly ancestral to birds. Paleontologists don’t agree with each other about the exact evolutionary relationship between birds and dromaeosaurs. Nevertheless, I catalogued this blog entry under ornithology.

The larger feathers found in the Eutaw Formation may be from an extinct species of hesperornthid, an aquatic dinosaur. Image from Dinopedia.
Alternately, the larger feathers may be from a species of dromaeosaur. There were dozens of families of dromaeosaurs alive during the Cretaceous. Image from UCMP Berkeley.

Scientists looked at these fossil feathers under a microscope and found structures that look similar to the bacteria involved in feather decay. However, these structures also look like melanosomes responsible for the color in feathers. The feathers from the shorebirds were likely gray, brown, or black. Whether these structures are feather-consuming bacteria or melanosomes is yet another point of contention between paleontologists. Fossils are a vague clue compared to a live organism.

Reference:

Knight, T.; S. Bingham, R. Lewis, C. Saurda

“Feathers of the Ingersoll Shale, Eutaw Formation (Upper Cretaceous) Eastern Alabama: The Largest Collection of Feathers from the North American Mesozoic”

Palaios V. 28 N. 51 May/June 2011

Refrigeration is Wonderful Technology

March 15, 2022

I bought a Kenmore refrigerator 18 years ago, and it is still working, but I decided to take pre-emptive action and replace it before it breaks down. It often shakes when it quits cycling, and I’m afraid it will cease functioning when the weather warms. Online sources suggest replacing refrigerators after 15 years, and I’ve been putting this off for a while. I’ve noticed house temperature makes a difference in how much the refrigerator labors. During the cooler months when our house is 67 degrees F, the refrigerator doesn’t cycle much, but during summer when the house is 77 degrees F, it seems to constantly cycle. I chose an energy efficient LG refrigerator to replace the Kenmore. It costs $830 to have it delivered from Lowes including hauling off the old one. 18 years ago, my Kenmore was priced at $800, showing inflation is minimal for refrigerators.

Refrigeration is an amazing invention, but I can track down no single person who invented electrical refrigeration. Instead, it seems to have been a collective advance in technology, and the concept was understood well before the widespread availability of electricity. As early as 1740 William Cullen, a Scottish scientist, demonstrated the principle of mechanical refrigeration, but he never made a usable refrigerator. Jacob Perkins invented a working refrigerator in 1838, but it failed commercially because nobody had electricity. John Gorrie invented an ice machine in 1842 to cool patients with yellow fever, but it was never used commercially to cool food. Breweries and meat-packing plants started using refrigeration in 1870 just when electrical power became more widely available. Albert Marshall patented the first mechanical refrigerator for home use in 1899, and this was followed by many other patented refrigerators at the turn of the century. At first refrigerators had to compete with iceboxes. Workers would cut big slabs of lake ice during winter and store the slabs in warehouses where they were insulated with sawdust. The ice was distributed to homes in urban areas. The ice slab was placed in the top of the icebox. The cool air sank and melting water would also cool the inside of the box. The ice had to be replaced every few days, and the melt water was a mess to clean up. Mechanical refrigerators began to replace iceboxes during the 1920s after William Durant introduced the Frigidaire model in 1918, and General Electric introduced their model in 1927. Nevertheless, many still referred to their refrigerators as iceboxes until well into the 1960s.

Before mechanical refrigerators people used iceboxes. Big slabs of ice were stored in massive warehouses where they were insulated with sawdust.
Old-fashioned icebox. Cool air sinks and melted water from the ice also cooled the inside of the box.
Early patented mechanical refrigerator.

The process of mechanical refrigeration is based on the principle of evaporation. When a gas cools it condenses to form a liquid. The evaporation of this liquid removes heat. Refrigerators have coils that hold refrigerant gases. Gas is forced into the coils inside the refrigerator where it cools to a liquid which removes heat from inside the refrigerator. The removed heat from this cooled liquid is turned into a gas that takes the heat into the coils outside the refrigerator. It is a self-contained system that cycles over and over.

Diagram from Science ABC showing the principle of mechanical refrigeration.