Pleistocene Sweet Potatoes (Ipomoea batatas)

November 24, 2015

Thanksgiving wouldn’t be complete without sweet potatoes and mashed Irish potatoes (Solanum tuberosum).  Both species originated in Central and South America, and paleo-indians were the first humans to eat them, possibly as early as 13,000 years ago.  Genetic and morphological studies suggest the sweet potato originated in the region located between the Yucatan Peninsula, Mexico and Venezuela.  The ancestor of the sweet potato is not known in the wild and may be extinct.  The modern sweet potato is likely a hybrid cross between this extinct wild ancestor and a species of morning glory (Ipomoea triloba).  Foraging humans may have gathered the sweet potato’s wild ancestor to extinction.  The oldest archaeological remnants of sweet potatoes were found in a Chilca Canyon cave.  Chilca Canyon is located near the south central Pacific coast of Peru, and it was much farther inland 10,000 years ago when paleo-indians left remains of their food here.  (At least 1 archaeologist disputes the age of this evidence.)  This region was a coastal savannah with some wooded areas then.  Remains of other species found in this cave in addition to sweet potato include Irish potato, olluca (Ullucus tuberosa), jicama (Pachyrhizos crosus), bottle gourd, and prickly pear.

Archeologists believe paleo-indians initially spread sweet potatoes and other edible plant species by accident.  All of the above mentioned plants will readily sprout from their tubers, roots, or seeds, if carelessly tossed in a garbage pile in contact with soil. By observing these accidents, paleo-indians learned to deliberately plant and care for these valuable plants when climatic conditions deteriorated and food became scarce.  Climate did become more arid along the Peruvian coast during the Holocene.  Native Americans settled near oasises located in a landscape that had transformed from savannah to desert.  Several archaeological sites in the Pampas de las Llamas region show that by 3500 BP native Americans were cultivating sweet potatoes, Irish potatoes, common bean, lima bean, oca (Oxalis tuberosa), oculla, peanuts, peppers, turban squash, avocado, edible canna (Canna edulis), cotton, bottle gourd, eggfruit (Pouteria lucuma), peanut butter fruit (Buchosia armeniaca), and manioc root.  The remains of wild game, marine mammals, and fish were also found at these sites.

Manioc root is poisonous, if not processed in a certain way.  When paleo-indians first colonized South America, they were unfamiliar with the many plants that grow in tropical climates.  The popular image of paleo-indians as meat-eaters is partially true, but an healthy human diet includes carbohydrates.  Surely, paleo-indians were aware that many plants were poisonous, yet the craving for carbohydrates drove them to take chances with unfamiliar roots, tubers, and fruits.  This trial and error likely led to many deaths or at the very least bad stomach aches.  But poisonous compounds are usually bitter.  This important clue helped guide the selection and processing of the unfamiliar plants.  Early people learned that some poisonous plants could be made edible by leaching the poisons in boiling water or by some other processing method.  They must have been really hungry for carbohydrates to make that much effort.  Paleo-indians got lucky when they discovered the wild ancestor of the sweet potato.  There is a species of morning glory (I. pondurata) with an edible root that ranges in southeastern North America.  Reportedly, cooks can rid the bitterness by boiling the root in several changes of water.  It’s likely the first sweet potatoes (a species of morning glory) had to be processed in the same way.  Paleo-Indians were rewarded with an extremely nutritious food.  Sweet potatoes are high in protein, carbohydrate, magnesium, potassium, sodium, phosphorus, vitamin C, B vitamins, and beta-carotene which the human body converts to vitamin A.

Thousands of years of deliberate cultivation has led to many delicious varieties of sweet potatoes that need no processing other than baking.  There are orange, yellow, white, and purple sweet potatoes.

Different varieties of sweet potatoes.

Scientists think the sweet potato is the result of a cross between this species of morning glory and another unknown ancestral species in the ipomoea genus.  Humans crossed them either accidentally or deliberately.

Ipomoea pandurata is a morning glory with an edible root that is native to southeastern North America.  The roots reportedly need quite a bit of processing to make them palatable. The seeds of I. violacca are used as an hallucinogen similar to LSD.

I like candied sweet potatoes with or without marshmallows, but I think the best way to prepare them is by simply baking them, then serving with plenty of butter and cinnamon sugar.  I use baked sweet potato flesh in pies I make with condensed sweetened milk, brown sugar, eggs, ginger, and nutmeg.  White sweet potatoes are drier but sweeter than orange sweet potatoes.  Yellow sweet potatoes were the most popular variety in the U.S. during the 1930’s but have since fallen from favor and are hard to find, yet they taste as good as the orange ones.

Sweet potatoes grown in Louisiana and Mississippi are marketed as “yams” but they are not true yams–a root rarely found in the supermarket.  True yams are not closely related to sweet potatoes but belong to the dioscorea genus.

Canna flaccida

Canna flaccida. The roots of the canna lily have also been eaten in Peru for thousands of years, probably since the Pleistocene.

















The remains of olluco (Ullucus tuberosus), another edible species  found in the Chilca Canyon caverns, date to possibly 10,000 BP.


Ugent, Donald; and Lande Peterson

“Archaeological Remains of Potato and Sweet Potato in Perus”

International Potato Center 1988

Zhang, D.P.; et. al.

“AFCP Assessment of Sweet Potato Genetic Diversity in 4 Tropical American Regions”

International Potato Center 1997-1998

Pleistocene Megafauna Wallows and Southern Appalachian Bogs

November 17, 2015

The wallowing, trampling, and foraging of Pleistocene megafauna probably maintained the open character of mountain bogs in the southern Appalachians during the Ice Ages.  Bogs were common natural environments during moist interstadials when cool temperatures reduced evapotranspiration rates and total precipitation increased.  Bogs occurred near the headwaters of mountains rivers and upper piedmont streams on flat poorly drained sites.  Boggy communities were “embedded” in mixed forests of pine, spruce, oak, and beech; and they provided a diverse array of habitats for wildlife.  Beavers created some bogs by damming streams.  The backwaters flooded depressions created by the wallowing activities of mastodons, horses, bison, peccaries, and possibly the extinct stag-moose (Cervalces scotti).  Scientists don’t know whether Cervalces scotti wallowed or not–some species of deer such as the present day moose wallow while other species do not.  Abandoned beaver ponds succeed to wet meadow communities consisting of herbs, grass, and sedge; thus attracting additional herds of megafauna that continued to maintain the open nature of the bog.  These vast wet meadows were ideal habitat for the extinct giant beaver (Casteroides sp.); a species that preferred to eat softer vegetation than its present day cousin.  Eventually megafauna herds migrated away and shrubby vegetation took over, creating yet another type of habitat.  Then, the shrubs gave way to trees such as red maple, sweetgum, tulip, black gum, pitch pine, and oak.  Beavers returned, removed trees, made dams, and the cycle began anew.

moose wallow

Moose wallow.

Picture showing Sweetgale Fen community

Sweetgale Fen in Maine.  This is a shrub-dominated fen.  Shrub and grass-dominated bogs may have been common in the upper south during moist but cool interstadials of the Pleistocene.

Bogs are replenished by precipitation.  During really dry cold phases of Ice Ages many of them dried up, but this type of environment never disappeared completely.  Cool temperatures slowed evaporation, allowing bogs to remain in mesic localities.

Bogs are acidic environments where sphagnum moss grows.  They differ from wetlands known as fens that are fed by groundwater.  Fens host neutral or alkali soils.  There are no true fens in Georgia because groundwater seeps through acidic bedrock.  The nutrient poor acidic soils of bogs support many interesting plants such as purple pitcher plant, alder, azalea, mountain laurel, cranberry, and blueberry.  They are all well adapted to poor acidic soils.  Pitcher plants obtain nitrogen from insects they trap in their leaves.  Alders can fix nitrogen from the atmosphere.  Members of the heath family (mountain laurel, azalea, blueberry, cranberry) have a symbiotic relationship with underground fungi that helps them extract nitrogen from soils with low levels of this element.

Mountain bogs are rare in Georgia today because they occurred on flatlands that were soon cultivated by European settlers.  A few still exist in Rabun and Union Counties.  They provide habitat for some bird species presently considered rare in the state including ruffed grouse, woodcock, and willow flycatcher.  This indicates these 3 species were abundant in the southern Appalachians during Ice Ages when bogs were more widespread.

Large mammals wallow in mud to rid themselves of parasites.  After the mud dries they scrape off the dirt by rubbing against trees or large boulders.  They wallow in the same places, creating depressions that alter drainage patterns and plant species composition.

Youtube video of an elephant wallowing.

I assumed all traces of megafauna wallows have disappeared over time, but E. Breck Parkman, a California archaeologist, believes he’s found an old megafauna wallow.  The site is known as the Mammoth Rocks and is located in northern California near the coast.  He’s found a depression next to the rocks.  He thinks this depression was used as a wallow, and the mammoths rubbed the mud off on the adjacent rocks.  He also thinks California’s vernal pools, an environment of mysterious origin, were former megafauna wallows.  Other potential “rubbing rocks” have been found in New Mexico, Texas, Minnesota, and Wisconsin.  It may be possible that Pleistocene-aged megafauna wallows may be present in Georgia.  Unusual depressions next to exposed rocky outcrops may be wallows.  However, paleo-wallows in Georgia are probably difficult to find and decipher.  Most have been filled with organic sediment, and many have been obliterated by agricultural practices.  Moreover, trees were more abundant than rocky outcrops.  Trees rubbed by extinct megafauna have long ago decayed to soil.

Mammoth Rocks

An archaeologist believes mammoths wallowed in this depression and used the rocks to rub off the caked dirt.  This site is known as the “Mammoth Rocks” and is located in northern California.  During the Pleistocene this region was a coastal prairie farther above sea level than it is today. Paleo-wallows like this may exist in southeastern North America but are probably harder to find because megafauna used trees instead of rocks to rub off dried mud.


Edwards, Leslie; and Jonathan Ambrose and L. Katherine Kirkman

The Natural Communities of Georgia

The University of Georgia Press 2013


Discarded Cans and Bottles are Death Traps for Shrews

November 12, 2015

During my wild oat days my friends and I would cruise old country roads and throw our empty beer bottles at road signs.  We did not know the superior hand-eye coordination that often led to smashed glass saved the lives of many a shrew.  Researchers examined nearly 3000 empty glass and plastic bottles and aluminum cans along a road in the Cherokee National Forest, North Carolina and found a total of 202 dead shrews and other small mammals.  One single container contained 8 trapped shrews alone.  Shrews like to crawl inside small holes for cover and to hunt for insects and mice, but the slick surface of glass or aluminum prevents them from gaining a footing, if the container is tilted at an angle of greater or equal to 15 degrees.  They will slide backwards when attempting to exit such a trap.  Eventually, they die of starvation or stress or they drown in rain water or the liquid remnants of the container.

3 shrews, a millipede, and a beetle were trapped and drowned in this discarded beer can.

The researchers found 8 species of small mammals trapped inside containers including 134 northern short-tailed shrews, 29 smoky shrews, and 5 southeastern shrews.  They also found the remains of other kinds of small mammals–19 white-footed mice, 4 deer mice, 7 woodland voles, 2 southern bog lemmings, and 1 house mouse.  Glass containers were deadlier because glass is slicker than aluminum.  A discarded container without the lid is a hell on earth for small mammals.  If you can’t hit a road sign, make sure you put that container in the trash.


Hamed, Kevin; and Thomas Loughlin

“Small Mammal Mortality Caused by Discarded Bottles and Cans along a U.S. Forest Service Road in Cherokee National Forest”

Southeastern Naturalist 14 (3) 2015

The Real Big Birds of the Pleistocene

November 9, 2015

I was a little too old for Sesame Street when PBS finally began broadcasting in northeastern Ohio circa 1972.  Nevertheless, I watched the show because it was something different.  Then, we didn’t have hundreds of satellite and cable networks, let alone a youtube that allows a person with internet to access millions of any kind of videos they can think of.  Instead, we were limited to the Cleveland and Youngstown affiliates of ABC, CBS, and NBC along with independent uhf channels from Pittsburgh and Cleveland.  The independent Pittsburgh station offered Rocket Robin Hood cartoons and poster board representations of Marvel superheroes that had audio dialogue.   The independent Cleveland station showed Shock Theater–double features of B movie horror flicks.  One had to endure a fuzzy reception to enjoy either station.  So Sesame Street was a kind of novelty compared to the limited options available then.

Big Bird, the iconic character who lives in the fictional world of Sesame Street, is much more famous than some real life big birds that lived from before the Pleistocene until well into the Holocene.

The fictional big bird of the PBS series Sesame Street is supposed to be 8’2″ tall.
Elephant birds were the largest species of bird to ever walk on earth.  They lived in Madagascar until ~1800 AD.  Humans likely overhunted them to extinction.  The largest species of elephant bird, Aepyornis maximus, grew as tall as 10 feet and could reach weights of 1100 lbs, and their eggs weighed 22 lbs.   There were 2 genera of elephant birds–Aepyornis and Mulleronis.  Scientists dispute the number of species in the Aepyornis genus.  Some think there are 4 species; others suggest all the fossil material belonged to just 1 species.
Illustration of the extinct elephant bird (Aepyornis maximus). 
Moas were another species of big bird that rivaled the fictional Big Bird of Sesame Street in size.  There were 11 species of moas native to New Zealand, the largest being Dinornis robustus.  It grew to 6’6″ tall and weighed over 500 lbs.  Humans reached New Zealand about 1400 AD, and they overhunted moas into extinction within 200 years.  Archaeologists have discovered big piles of moa bones in human settlements, and the extinction of these birds is considered an excellent case study of humans overhunting species of vertebrates to extinction.
Last of the moas. Humans killed off the giant birds by overhunting, a new study says, although the hunters did not use bows and arrows.
11 species of extinct moas roamed New Zealand until humans overhunted them into extinction.  They did not use bows and arrows as the illustration depicts.
Elephant birds and moas belong to a family of birds known as the ratites which also includes ostriches, emus, cassowaries, rheas, kiwis, and tinamous.  All of these species, with the exception of tinamous, are flightless ground dwelling birds.  The ratites live on continents that were once part of the supercontinent Gondwanaland.  Formerly, scientists believed the ratites shared a common ancestor from when Africa, Australia, and South America were part of Gondwanaland and later evolved into different species after Gondwanaland split apart.  I mentioned this belief in my post about the temporary ostrich colonization of India during the Pleistocene. (See: )  However, a new study of ratite DNA determined tinamous, birds that can fly, are closely related to the extinct moas.  (Tinamous were thought to be distant sister taxa to the ratites before this study.)  This finding suggests each species of flightless ratite independently evolved flightlessness from birds that flew to each southern hemisphere continent after Gondwanaland split apart. This is the best explanation for the close relationship between the tinamous and the moas because it’s unlikely that flightless birds would re-evolve the ability to fly.  These speciation events occurred when the continents were closer than they are today, so that the distances were easier for flying birds to traverse.  After a population of tinamou-like birds established a colony on a new continent, they encountered an ecosystem that had just recently lost dinosaurs to the K-T extinction event.  The ratites evolved as an ecological replacement for at least some of the dinosaurs in regions where birds faced less competition from mammals.

Proposed evolutionary relationships between the ratites based on molecular DNA evidence.

There are 47 species of tinamous.  They are native to South America, Central America, and southern Mexico.  They nest on the ground but will roost in trees and are omnivorous, feeding upon fruit, plant matter, insects, worms, and herpetofauna.  There are some anatomical similarities that suggest tinamous are related to other ratites, but if not for DNA evidence, scientists would never know that they are ratites themselves.

Brushland tinamou (Nothoprocta cinerascens).  Tinamous are closely related to extinct moas of New Zealand.  Because they can fly, scientists consider this evidence that all flightless ratites evolved independently from birds that were able to fly over ocean water.


Mitchell, K.J.; et al.

“Ancient DNA Reveals Elephant Birds and Kiwis are Sister Taxa and Clarifies Bird Evolution”

Science 344 2014

Large Pleistocene Carnivores Kept Megaherbivore Populations in Check

November 4, 2015

A brand new study suggests large packs of big carnivores kept populations of megaherbivores in check during the Pleistocene.  This finding seems like a no-brainer, but some paleoecologists believe megaherbivores suffered little mortality attributable to predation and were instead limited by the availability of plant resources.  The results of this study imply that large carnivore predation of megaherbivores was beneficial for the environment as a whole.  Lowering the overall population of megaherbivores prevented the landscape from being denuded and protected vegetated habitats for birds and other small animals.

The authors of this study compared tooth size and shoulder height between large Pleistocene carnivores and modern carnivores.  They determined that Pleistocene carnivores were on average 50%-100% larger than modern day carnivores.  This greater size gave them the ability to better prey on megaherbivores.  Even though these carnivores were larger, they likely needed to hunt in packs to take down such megaherbivores as mammoth, mastodon, and ground sloth.

Elephant survives attack by 14 Lions

Lions attacking a juvenile elephant.  A brand new study suggests Pleistocene carnivores in large packs regularly killed juvenile megaherbivores, keeping their populations in check so they didn’t destroy their environments.  Lions jump on the backs of baby elephants while other members of the pride chew through the tendons.  Incidentally, this individual eventually escaped.

The authors of this study also looked at modern incidences of predation on megaherbivores.  They noted that lions killed 74 elephants in Botswana over a 6 year period.  60% of these elephants were under 9 years old–evidence juveniles were easier to kill.  Lions killed 49 elephants over a 6 year period in Zimbabwe.  16% of black rhinos under the age of 2 were killed by lions or hyenas.  Hyenas killed 5 juvenile elephants in Hrange National Park, Kenya in 1 year.

Early European explorers reported much larger prides of African lions than are found there today.  Some saw prides of 40 lions in sparsely populated areas of Africa.  The authors of this study infer Pleistocene carnivores roamed the range in groups this large.  This may be true for American lions (Panthera atrox) and dire wolves (Canis dirus), but I’m of the opinion that saber-tooths (Smilodon fatalis) were for the most part solitary predators, though mothers with nearly full-grown cubs likely did gang attack juvenile megaherbivores.  Their specially evolved canines were an adaptation to slicing through thick-skinned necks.


Valkenburgh, Blaire; et. al.

“Large Violent Animal Attacks Shaped the Ecosystems of the Pleistocene Epoch”

PNAS October 2015

Mountain Gorilla (Gorilla beringei) Influenced Landscapes in Equatorial Africa

October 30, 2015

Gorilla costumes are popular on Halloween.  There is something frightening about a gorilla.  They resemble humans but are bigger, much more powerful, and hairy.  Moreover, they’re armed with sharp canine teeth.  For tens of thousands of years gorillas were better adapted to some environments than technologically primitive humans.  Gorillas can survive with more success than naked unarmed humans (See the tv series Naked and Afraid on Discovery Channel) in lowland tropical jungles and cold vegetated highlands.  But the human population has exploded in recent centuries, and people are infringing on gorilla habitat.  Though no physical match for a gorilla, humans do use projectile weapons to slaughter their cousin apes.  I think a man who would enjoy hunting a gorilla would also have no qualms about shooting his neighbor for the hell of it.  In reality humans are much scarier than gorillas.

Mountain gorillas significantly modify their environment.

Scary Gorilla | Photos Of Gorilla Fighting 1 500x356 Photos Of Gorilla Fighting: Animal Pics, Jungles, Animal Pictures, Silverback Gorilla, Jiu Jitsu, Awesome Pictures, Amazing Pictures, Sunday Funday, Animal Funny

Gorillas are much more powerful than humans.  An unarmed human would stand no chance in a fight with one.  They could literally tear the arms off the top human MMA fighter.  I mean pulling the arms off at the shoulder socket and tearing them off with the skin attached.

Mountain gorilla habitat is shaped by many forces.  They live between 7200-14,000 feet in elevation, an environment known as equatorial highland.  The high elevation keeps temperatures cool and catches rain clouds, resulting in moist conditions, but the location near the equator is frost free, fostering the year round green vegetation gorillas need because their diet is almost completely vegetarian.  Volcanic activity, rocky landslides, bamboo die-offs, fire, and gorilla and elephant foraging create conditions favorable for the low level plant growth that can support gorilla populations.  According to Jonathan Kingdon, gorillas chase duikers, buffalo, and elephants away from their favorite feeding grounds.  Before they learned to fear men with projectile weapons, I suspect they chased humans away too.  Just imagine Pleistocene humans encountering gorillas for the first time.  It’s likely these people were walking along with just spears.  If the gorillas felt threatened and attacked quickly enough, the first humans to see them  probably fled for their lives.  Alas, today there are only 620 mountain gorillas left in the wild.


Mountain gorilla family group feeding in habitat

Mountain gorilla habitat.  Lots of low level vegetation due to the variety of factors mentioned above.

Mountain gorillas (Gorilla beringei) diverged from western lowland gorillas (G. gorilla) during the early to mid Pleistocene Ice Ages when savannah habitat expanded and isolated gorillas into forest refugia.  Gorillas can’t survive on savannahs because those environments are subject to long droughts and won’t support the plants gorillas need to eat.  Genetic studies suggest this divergence occurred at least 261,000 years ago during the Illinois Ice Age.  Eastern lowland gorillas expanded their range following the end of the last Ice Age ~15,000 BP when forest habitat expanded.  Eastern lowland gorillas are the same species as mountain gorillas.  There are 4000 eastern lowland gorillas left in the wild.  Western lowland gorillas still have an healthy population of an estimated 100,000.


Anthony, Nicola; et. al.

“The Role of Pleistocene Refugia and Rivers in Shaping Gorilla Genetic Diversity in Central Africa”

PNAS 2007

Carvers Creek State Park in South Central North Carolina

October 27, 2015

Last Saturday, we visited my nephew who is stationed at Fort Bragg in North Carolina.  This gave me the opportunity to hike around Carvers Creek State Park located nearby.  Past the entrance, a long wide path borders an old field on one side and a woodland of shortleaf pine with an understory of blackjack oak and sweetgum saplings on the other side.  I heard a constant chirping of crickets in the field, and grasshoppers were also abundant.  This is ideal habitat for loggerhead shrikes (Lanius ludovicianus), a species in decline.  They nest in short trees but hunt for large insects (such as grasshoppers), mice, lizards, amphibians, and even juvenile venomous snakes; all of which can be found in this old field.  I’ve never seen a loggerhead shrike, and it’s high on my birding wish list.  I asked a park ranger where the shrikes were.  She told me they could usually be seen behind a fence where they keep their maintenance equipment, and birders using binoculars could stand near the fence and see them.  I didn’t have binoculars with me, so shrikes are still on my wish list.


The first part of the trail borders an old field humming with crickets and grasshoppers.  Loggerhead shrikes inhabit this park.


Much of the park is open woodland/savannah type environments.


Big loblolly pine.

This path leads to the former winter house of one of the Rockefellers, but it is not yet open to the public.  The state park service probably needs to renovate it, so it’s safe for visitors.  Rotten floor boards can be hazardous.  It overlooks a millpond and has glassed-in porches on the 2nd floor of both the front and the back.


The front of the WWI era Rockefeller winter home.


Back of the Rockefeller winter home.  Most of the wildlife I did see was here behind the fence.  Note the glassed-in porch.  Nice.  It overlooks the millpond.


Cypress trees ring the millpond.



A live oak tree grows near the Rockefeller house.  Live oak is not native to North Carolina this far inland, though it does grow near the coast.  This specimen must have been transplanted here over a century ago.  I saw gray squirrels, chipping sparrows, and blue jays foraging on acorns under the tree.  One of the squirrels was rather large, and at first I thought it might be a fox squirrel, but I caught a glimpse of white underbelly.  Gray squirrels usually have white bellies, while fox squirrels are solid-colored.  The ranger told me fox squirrels can be seen on the loop trail around the millpond, but I didn’t see them.


Live oak.


The loop trail goes through a savannah.


More open woodland/savannah.

I was surprised to see cypress trees growing this far inland.  Cypress trees grow on the edges of the millpond here.  I checked the range map and learned this site is about as far inland as they can normally be found.

The loop trail threads through open pine savannah.  I noticed fire marks on some of the pines.  This park must be managed with fire.


The millpond is u-shaped. Note the cypress trees in the water.

Carvers Creek Park is a recent and valuable addition to North Carolina’s state park system.  Much of the area around the park has been transmogrified into pine tree farms, an environment that supports almost no wildlife at all.


Hitchcock Woods in Aiken, South Carolina

October 22, 2015

I visited Hitchcock Woods in 1990 and was not impressed then.  I considered it a boring pine-dominated woods.  However, South Carolina Educational Television recently showed episodes of Naturescene and Expeditions with Patrick McMillan that both featured this park, and I learned more about it and what to look for.  I revisited Hitchcock Woods this past Sunday and with more knowledge of the site, I had a much more favorable impression than I did 25 years ago.

William Hitchcock donated a 1200 acre stretch of woods to the city of Aiken, S.C. in 1939.  The Hitchcock Foundation has since added nearly 800 acres, so that there is about 3 square miles of wilderness in the middle of Aiken.  The trails are wide and sandy and littered with horse manure.  Horseback riding is popular in this town.

The soils consist of sand and kaolin clay that formed during the Cretaceous Age over 66 million years ago when this region was seashore.  The sandy clay soil is unproductive for agriculture and most of Hitchcock Woods has never been under cultivation.  It has also never been clear cut, though selective logging is part of the management plan for the woods.  I saw a great variety of trees here including southern red oak, post oak, water oak, black oak, white oak, overcup oak, red maple, silver maple, hickory, magnolia, persimmon, dogwood, loblolly pine, shortleaf pine, longleaf pine, slash pine, and Virginia pine.


The soil here is sandy with nodules of kaolin clay.


Tall old growth trees grow in these woods.


A great variety of trees grow here.


The trails are wide and sandy and littered with horse manure.


More old growth hardwoods.

There are several interesting disjunct species here that are relics from earlier climatic phases.  The poor soils that prevail are a condition favorable for their continued existence at this locality, since they’ve disappeared from the rest of the region. Sandhill rosemary (Ceratiola ericoides) currently grows on the sandhills of Florida.  A relic disjunct population occurs in Hitchcock Woods.  This species likely was more widespread throughout southeastern North America during the late Pliocene/early Pleistocene when the region suffered through an especially arid climatic phase.  However, it may also have been more widespread during the most recent Ice Age Maximum about 20,000 years ago because climatic conditions were quite dry then as well.  Disjunct populations of Virginia pine (Pinus virginiana) and mountain laurel (Kalmia latifolia) are also Ice Age relics that likely occurred throughout the region during colder climatic stages.


Virginia pine growing around the chalk cliffs is a disjunct species normally found in the mountains.

Many of the trees in Hitchcock Woods are at least 200 years old.  Some longleaf pine trees (Pinus palustris) have red-cockaded woodpecker (Dryobates borealis) nesting cavities.  This species is the only woodpecker that makes nesting cavities in live longleaf pine trees.  The oozing sap repels predatory snakes seeking to eat nestling birds.  After years of fire suppression red-cockaded woodpeckers disappeared from Hitchcock Woods.  They require open conditions.  The Hitchcock Foundation began managing prescribed fires 20 years ago, and the red-cockaded woodpeckers could be re-established here some day.  For now the park’s 5 other species of woodpeckers use these cavities.


I think this is a longleaf pine.  Some longleaf pines in Hitchcock Woods may be more than 200 years old and have red-cockaded woodpecker nesting cavities, though the birds have been extirpated from this area.

A population of fox squirrels (Scirius niger) lives in Hitchcock Woods.  The gray color phase predominates here.  Fox squirrels are uncommon and local in Georgia and South Carolina.  I hypothesize fox squirrels have difficulty recolonizing forests that have been clear cut.  The young dense forests that resprout following clear cuts are more favorable for gray squirrels (Scirius carolinensis).  Gray squirrels are more nimble and can escape predators by jumping from tree top to tree top.  Fox squirrels prefer racing across the forest floor to escape predation.  The presence of fox squirrels in Hitchcock Woods suggests they were formerly more common in southern forests before they were clear cut. I was hoping to see a fox squirrel, but they are more active in the morning, and my hiking companion doesn’t get out of bed until nearly noon.

Rain has eroded the clay and sand here into chalk cliffs.  This is where I found Virginia pine trees.


Chalk cliffs are a naturally eroded environment.


Another view of the chalk cliffs.

The Sand River is another interesting geological anomaly in Hitchcock Woods.  Water flows down this creek following a rainy spell, but normally it’s just a river of sand.  It’s located on the other side of Hitchcock Woods from the chalk cliffs.  I’ll visit that part of the park another time.

Ecological Islands within the Continent of Africa (Part 4–the Zaire Basin)

October 19, 2015

The Ndoki forest, located in the Zaire basin, was probably untouched by man until about 25 years ago.  Archaeologists believe it was never inhabited by modern man (Homo sapiens).  Local tribes avoided the forest because they feared a monster described as being similar in appearance to a pre-historic plesiosaur.  Witnesses weren’t lying, but what they likely saw were forest elephants (Loxodonta cyclotis) walking across deep river bottoms with their heads and trunks exposed.  This would resemble a plesiosaur.  When lumber companies began exploring the forest, the animals were naive and unafraid of people.  The Ndoki forest is now protected but selective logging is allowed in the areas around the park.  This park is rich in wildlife–elephants, buffalo, antelope, hogs, and primates abound.

The okapi (Okapi johnstoni) is only found in this region.  It is a giraffid, a family of ungulates that were formerly more widespread.  There were 17 genera of giraffids during the Miocene about 20 million years ago, but today there are 2 genera of just 1 species each–the okapi and the giraffe (Giraffa camelopardalis). Giraffids have long dark tongues, skin-covered horns, and lobed canine teeth.  Okapis were more widespread in Africa during the Pleistocene.  Anthropogenic fires and hunting, along with competiton from antelopes, may have driven them to relic status.  As a whole, deer and antelope have ecologically replaced giraffids in Eurasia and Africa respectively.

Image of an okapi

The okapi is a relic of the giraffid family.  They were once widespread over Eurasia.  Giraffids have been ecologically replaced by antelope and deer.

Alternating wet and dry climate cycles have influenced evolution and caused the speciation of many new organisms in this region.  Bush babies (Galongo sp.) are tiny primates adapted to eating sap and insects.  They likely evolved from fruit-eating primates during dry climate cycles when trees didn’t produce enough fruit to eat.

Bush babies are adorable little primates.

There are over 20 species of guenon monkeys in this region.  These tree-dwelling primates evolved from ground-dwelling primates during wet climate cycles when forests replaced savannah.  Dry climate cycles limited forests to isolated areas along the river and isolated populations of monkeys evolved into different species.  Following a return to wet conditions and expanded forests, these new species of monkeys came into contact with each other.  Some hybridized, creating still new species, while others did not.  This explains why this region hosts so many species of monkeys that occupy similar ecological niches.


The giant genet is endemic to the Zaire basin.  I could not find a good photo of this species online.

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Wolf’s monkey (Cercopethicus wolfi) is 1 of many species of guenon monkeys that live in the Zaire basin.

This region is also home to the bonobo (Pan paniscus), a chimpanzee that is more peaceful than its violent warlike cousin (Pan trogolodytes).  They would likely be wiped out, if P. trogolodytes invaded their range.

Small parakeets, known as lovebirds, have also evolved into new species here in response to climate changes.  There are 7 species in this region.

The collared lovebird (Agapornis swindernianus) evolved from an Asian species that crossed savannah then became adapted to tropical forest.


Kingdon, Jonathan

Island Africa: The Evolution of Africa’s Rare Animals and Plants

Princeton University Press 1989

Ecological Islands within the Continent of Africa (Part 3–The Forests of Biafra)

October 13, 2015

The bight of Biafra, the “armpit” shaped region of western Africa, hosts the wettest rainforests on the continent.  Over 6000 species of plants grow here including oil date palms, and many species of cassia trees, liana vines, and orchids that sprout in organic matter deposited on the crooks of tree branches.  Before humans deforested the greater part of the region, it was a lush, green, and shady environment.  Species such as the giant ginger plant (Aframomum gigantea) exist as long-lived roots until a tree falls, allowing sunlight to reach the forest floor.  Then the ginger plant sprouts up to 18 feet tall to benefit from life-giving photosynthesis.  The spicy hot compounds in the root protects the ginger from foraging animals, insects, and microbes for decades while the plant awaits its chance to sprout.  The stems, however, are a favorite food of the gorilla.  Ginger is used in human cuisine, but try taking a bite of raw ginger root and find out why animals avoid eating it.

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Illustration of the giant ginger plant.

Primates and squirrels like to eat the nuts of the 20 species of colas that grow here.  Yes, this is the nut that flavors Coca-Cola.  The caffeine in the nuts is poison to some animals but many species, including humans eat them.

予約商品[コーラの木]コーラ・レピドータ(Cola lepidota)種子

Cola nuts are native to Africa.  Extract from the caffeine-laden nuts is used to flavor Coca-Cola.

The American persimmon (Diospyros virginianus) is 1 of just 2 species of ebony trees native to North America.  Africa has 40 species in this genus.  They produce a heavy valuable wood, a trait that has led to deforestation of the region.  The fruit of ebony trees resemble those of American persimmons and are edible, but the leaves are toxic.  An area of Biafra, known as the Sanaga Delta, experiences heavy rains and has sandy soils.  Ebony trees thrive on these poor soils and dominate the forest canopy.  The toxins in the ebony tree leaves help the trees conserve nutrients by discouraging animals from eating them.  Most colobus monkeys primarily eat leaves but can’t eat the toxic ebony tree leaves.  Therefore, most species of colobus monkeys live in lower densities on the Sanaga Delta than elsewhere in Biafra.  But the satanic colobus monkey (Colobus satana) evolved the ability to eat seeds and do better here with reduced competition from other monkeys.

Diospyros crassiflora

Ebony trees are endangered because of the high quality dense wood they produce.  Most fruits are edible, similar to American persimmons, but the leaves are toxic.

The satanic or black and white colobus monkey.

The mandrill (Mandrillus leucopheus) evolved from a ground dwelling baboon-like monkey.  It became adapted to more forested conditions.  The colorful faces and genitals of the males is likely an adaptation to communal living in the forest.

A male drill (Mandrillus leucophaeus). Photo by: Ola Olsson.

Male mandrill.

Over 1000 species of butterflies live in Biafra–the richest diversity in the world–and over 500 species of birds occur here, rivaling the Amazon basin’s diversity.  There are 8 endemic genera of frogs as well.  The goliath frog (Conraua goliath), weighing over 7 pounds, is the largest frog in the world.  This species occurs in a small range within Biafra.  Its large size and slow rate of reproduction make it vulnerable to predation, yet it has found a survivable niche in this rich region.

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The goliath frog is endemic to this region.  It can weigh over 7 pounds.


Kingdon, Jonathan

Island Africa: The Evolution of Africa’s Rare Animals and Plants

Princeton University Press 1989


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