Four Stone Hearth Letters

The Four Stone Hearth is a blog carnival that specializes in anthropology. Anthropology is the study of humankind, throughout all times and places. This discourse focuses primarily on four lines of research:

* socio-cultural anthropology
* bio-physical anthropology
* archaeology
* linguistic anthropology

Each one of these subfields represent a stone in our hearth, a blog carnival aims to publish content from all aspects of the blogosphere. Click “Read More” below to see this week’s issue!

The Four Stone Hearth Tablets

Decades ago, archaeologists discovered in an ancient tell that has since been bulldozed to make way for a McDonalds (would you like fries and a Coke with your provenance?) four clay tablets of cuneiform script but in a language as yet undeciphered –until today!

The language is new and has been named Carnival and is spoken in various ancient lands, including FrStnHrth. All we have are the consonants, so by plugging in a soft e sound, we get FerStenHerth, a land that suffered the fate of others during the collapse of the Bronze Age and the attacks of the Sea Peoples. Below is a translation of these tablets.

ArchaeologyTablet 1: Archlgy

Alun’s Letter
To Nefer-khepru-re, Great King, king of Egypt, thus speaks Alun Salt, Great King, king of Archaeoastronomy, your brother. I and my house, my horses and my chariots, my notables and my land, we are well. May well-being reign over my brother and his house, his horses and his cars, his notables and his land.

I present to you the problem of The Orientation of Roman Camps, to which I have treated the data as a binomial distribution. This debate about Roman Camps, which appears on the hallowed tablets of the Oxford Journal of Archaeology, is of great concern my brother. I vented my anger with my brother with the following words: Should my brother not know that I am ill? Why has he not supported my head? Why has he not worried and sent his messengers? These Romans will surely be the end of the Bronze Age!

A Letter From Tim Ruler of Remote Central to the King of Egypt
To Nibmuaria, King of Egypt, my brother, say: Thus says Tim, King of Remote Central, your brother. It is well with me. May it be well with you; with your household, your wives, your sons, your nobles, your warriors, your horses, your chariots, and throughout your land may it be very well… [23 more lines of well-wishes destroyed]…

Behold, one chariot, two horses, one male servant, one female servant, out of the booty from the land of Hatti I have sent you. And as a gift for my brother, the stone tools of a civilization in a far away land of a far away time [The cuneiform hyperlink is reconstructed from similar tablets]: Walker Hill a Pre-Clovis Site: MN Archaeologist Says No.

Fragment of a letter from Paul, King of Wannabe, to Akhenaten, King of Egypt
And now, as to the tablet you have sent me, why have you put the name of my brother above my name? And who is it who troubles the good relations between us? Has such behavior become custom? My brother, have you written to me thinking that we become allies? If you are my brother, why have you praised my name, when I am no better thought of than a cadaver? […] But your name […] I rub out […] surely as the Toltec of a far away land rubbed out the Maya of Chitzen Itza!

A Letter From Martin Rundkvist Lord of Aardvarchaeology
To the king, my lord, my god, my Sun: Message of Abi-Milku, your servant. I fall at the feet of the king, my lord, 7 times and 7 times. I am the dirt under the sandals of the king, my lord. My lord is the Sun who comes forth over all lands day by day, according to the way (of being) the sun, his gracious father, who gives life by his sweet breath and returns with his north wind; who establishes the entire land in peace, by the power of his arm : ha-ap-si; who gives forth his cry in the sky like Baal, and all the land is frightened at his cry.
The servant herewith writes to his lord that he heard the gracious messenger of the kind who came to his servant, and the sweet breath that came forth from the mouth of the king, my lord, to his servant–his breath came back! The message carried is of the Oscarian Archaeology Journal On-Line!

Physical AnthropologyTablet 2: PHSCL ANTHRPLG

A Letter from Jeremy Bruno to Amenhotep III
To my lord, my king, my gods, my sun, this is said:
Jeremy, the dust of thy feet, at the feet of my lord, my king, my gods, my sun, seven times, and seven times more, I fall down. Behold, true to my lord, my king. I look on one side, and I look on the other side, and there is no light; but I look on my lord my king, and there is light. A brick may move away from under the coping, but I shall not move from under the feet of my master.
Let now my lord my king enquire about me of the AAAS Symposium: The Reduction of the Hominid Species.

Letter from blgtnjew, Prince of Hominin Dental Anthropology, to Akhenaton
To the Great One, thus speaks BLGTNJEW, at your feet do I fall.
You must know that Shipti-Ba’al and Zimrida are conspiring, and Shipti-Ba’al has said to Zimrida:
Many people seem to think that the bones and teeth of our ancestors as well as previous generations leave us with little information. In fact, that is not true. The bones and teeth of our ancestors, whether they are hundreds or millions of years old, can tell us a vast amount of information.

More on this revelation of dental conspiracy on another tablet still in my kiln [cuneiform hyperlink reconstructed], Basics: Dental Anthropology.

A Letter from Yann Klimentidis to Tiye
To Tiye, Lady of Egypt. Thus speaks Yann Klimentidis, King of Yann Klimentidis’ Weblog. May everything be well with you. May everything go well for your house, your son, may everything be perfectly well for your soldiers and for everything belonging to you. Everything is well with me and I am keeping with my theme on the climatic conditions during the major stages of human evolution. Visit with me and hear my thoughts on Paleoclimate and Human Evolution.

A Letter from Greg Laden to Akhenaten
To the king, my Lord, thus speaks Greg Laden, [your] servant. [I have prostrated myself] seven times seven times at the feet of my Lord, the king. The city of […] I have entered. May [the king] know that all the countries are at peace, (but) there is war against me and it is said by Mims We Shouldn’t Be Surprised That Chimps Hunt With Spears. With humble regard to Mims on Chimps: I agree and disagree. Thus, then, may the king take care of the troops of archers. May he send troops of archers against the Chimps who commit evil deeds against the king, my Lord.

A letter from Kambiz of
To the king, my lord, my god, my Sun: Message of Kambiz, your servant. I fall at the feet of the king, my lord, 7 times and 7 times. I am the dirt under the sandals of the king, my lord. My lord is the Sun who comes forth over all lands day by day, according to the way (of being) the sun, his gracious father, who gives life by his sweet breath and returns with his north wind; who establishes the entire land in peace, by the power of his arm : ha-ap-si; who gives forth his cry in the sky like Baal, and all the land is frightened at his cry.

The servant herewith writes to his lord that he heard the gracious messenger of the kind who has One more word on, and a video of, chimps hunting with spears. As you no doubt have heard from my king brothers, these Chimps threaten our cities as the Savanna Chimpanzees Hunt with Tools.
Is this breaking news: Chimps hunt using spears?

Letter from Kambiz of
To the king, my lord, my god, my sun, the sun in the sky. Thus says Kambiz, the amelu of, ruler of FerStenHerth, the dust of your two feet, the stable-man of your horse, the Sonny to your Bono: At the two feet of the king, my lord, the sun in the sky, seven times and seven times I prostrate myself both upon the belly and back. And to all that the king, my lord, has told me I have paid close attention. I am the king’s servant and the dust of your two feet.

Let the king, my lord, be aware that my beef is not with what Yann and afarensis are reporting, but the people who are theorizing this all. Hold court with me and share A brief critique about the extinction of Neandertals due to climate change

LinguisticsTablet 3: LNGSTCS

Letter from Corcaighist to FerStenHerth
To FerStenHerth, the ruler of Blogosphere say: Thus says the king: He sends this tablet to you, saying to you, Be on your guard; guard the place of the king where you are. Pay close attention to what he tells you so that the king does not find fault in you. Everything he tells you, pay careful attention and carefully carry it out. And be on guard! Be on guard! Do not be negligent.

Bealocwealm hafað fréone frecan forth onsended,
Giedd sculon singan gléomenn sorgiende,
On Meduselde pæt he ma no wære,
His dryhtne dyrest and mæga deorost.

Read the remainder of Éowyn’s lament at [cuneiform hyperlink reconstructed] Bealocwealm hafað fréone frecan forth onsended.

A Letter from Katie, Princess of TEFL Logue, to Akhenaten
Let the king my Lord hear the word of his servant!
Zirdamyasha has withdrawn from Biryawaza. He was with Shuta, the servant of the king in the city of [………] and I said nothing to him, but he deserted to me, and now Shuta has written to me: is Frananglais: A Compromise Language?!’ But I did not consent to give him up. Behold, Accho is (as Egyptian) as Magdal in Egypt, but the king my lord has not heard that Shuta has turned against me. Now let the king my lord send his commissioner to fetch him.

EthnographyTablet 4: ETHNGRPHY

Letter from Robert Philen of Robert Philen’s Blog

To the king, my Lord and my God and Sun, thus speaks Robert Philen, your servant, the dust under your feet. At the feet of the king, my Lord and my God and Sun, seven times and seven times I prostrate myself.

I have heard the words that the king wrote to me and who I am that the king lose his land through my fault? I am the servant of the king, and I have not rebelled and I have not sinned, and I do not retain my tribute, and I do not disregard the demands of his commissioner. They defame to me with ill will, but may the king, my Lord, not accuse me of revolting!

Moreover, my crime is, so they say, that I discovered Bertrand Russell’s Chicken: Sign Experience and the Human Mind!


I hope you enjoyed the creative license I took with this week’s Four Stone Hearth. In case you didn’t get it, I modeled the “letters” above after the Amarna letters, copying some of them verbatim and substituting names and websites. There are one or two mild gags hidden in the text here and there, but nothing spectacular. At least three of the links were sent to me by bloggers other-than-the-authors, specifically the links in the Linguistics and Ethnography sections.

My hope was to make this week’s Four Stone Hearth fun and desirable for future iterations. There are a LOT OF ANTHRO BLOGGERS OUT THERE! Send your posts! Get some traffic! Find a sense of communitas (to invoke Victor Turner) and liminality!

The next Four Stone Hearth will be hosted at on March 14th.


Forbidden Archaeology? Some So-Called Out of Place Artifacts

I visit various internet sites each week that range from the scientific to the down right kooky. I must confess that “Kooky” fascinates me. But even on the science sites that have active message boards, there are frequent mentions of so-called “out of place artifacts” (OOPA’s?). Very often, these “artifacts” are used by someone to “prove” a conclusion they already have about the age of the planet or a greatly exaggerated antiquity of humanity. Ironically, I’ve observed that some of these artifacts can be simultaneously used by different proponents of contradictory claims to support both a “young Earth” and an ancient humanity (millions of years).

Below the fold, I’ll discuss some of the “top ten out of place artifacts” as claimed by that infamous ragazine, Atlantis Rising (Jochmans 1995). The list is over 10 years old, but they are among the more commonly mentioned artifacts.

The Baghdad Battery
The very first item on the Atlantis Rising list is the infamous “Baghdad battery,” a clay pot dating to around the 3rd century CE and found in Iraq. Often referred to as a “battery” by significance-junkies and mystery-mongers, it obviously isn’t since there were no electrical devices present in the early first millennium for which a battery would be required. But, of course, this is exactly the sort of thing the significance-junkie looks for. Suddenly, an innocuous clay pot becomes part of a grand conspiracy to which archaeologists are willing accomplices in a cover up. Ignored are the more probable explanations for such jars, one of which includes that vessels of this type were for scroll or papyrus storage. They were typically 5 inches long and contained a rolled up copper sheet and an iron rod. The ends were capped with asphalt plugs, which would have interfered with the conduction of electricity.

They would, however, have been very efficient at hermetically sealing papyrus and, since each of the “batteries” found to date have were found open to the environment while in situ, any papyrus inside would have long since deteriorated, leaving a slightly acidic residue. Experiments testing the “battery” hypothesis yielded about 25mW from one of these tested as a possible galvanic cell. A penlight requires about 1100mW. Tests were conducted since a couple of electricity-related hypotheses exist regarding the purpose of these jars: a way for electroplating metals such as gold or elektrum; and for ritualistic use by some “magical” means by a sorcerer who used a weak acid in the vessel and attached it to metal statue. Touched by believers, they would then feel a tingle, verifying his “power.” The former suggestion of electroplating has fallen out of favor, however, since gilding metal by fire using mercury is far more effective. Very little gilding was able to be procured from models of the “batteries” which only produced a very weak current.

“Electron Tubes” from Dendera, Egypt
Atlantis Rising lists this as their #2 OOPA and it’s a relief of the Late Ptolemaic period’s Temple of Hathor in Dendera, Egypt. Atlantis Rising describes the relief as depicting “cathode ray tubes,” verified by no less than three electronics engineers or technicians! Somehow, we’re to accept that the engineers and electricians aren’t to succumb to their credulity or find undo significance in a graphic relief that has accompanying texts which state the “cathode ray tubes” to be on a solar bark, the barge used by Ra (the sun god) to traverse the sky. The “tubes” are symbols of fertility, specifically a lotus held by Horus with an emerging snake.

“Neanderthal” Skull with a “Bullet Hole”

Listed as its #8 OOPA, Atlantis Rising claims that a 38,000 year old Neanderthal skull, excavated in 1921 in present-day Zambia and residing in the Museum of Natural History in London is from victim of a rifle shot to the head. The Atlantis Rising article states the wound is a neat entry hole with “no radial split lines” and a shattered cranium opposite the hole as an exit wound. From the article:

If such a weapon was indeed fired at the man, then one of two conclusions can be made: either the specimen is not as old as it is claimed to be, and was shot by a European in recent centuries, or the remains are as old as claimed, and the marksman was ancient too.

Of course, its the latter conclusion that significance-junkies and mystery-mongers at Atlantis Rising arrive at, though I’m sure there are no shortage of young-earth creationists willing to buy into the former.

The article misses the mark on some basic information right off the bat. The skull, known to paleoanthropologists as the Kabwe skull and sometimes the “Broken Hill Man,” is dated to between 125,000 and 300,000 years old, not 38,000. It was also found in a limestone cave, not 65 feet down in “lead rock,” as Atlantis Rising suggests. I took particular issue, as I’m sure many readers familiar with hominid evolution did as well, with the claim of “Neanderthal” associated with a skull found in Zambia. Surely Neanderthals in Zambia is newsworthy by itself, never mind the “bullet” hole!

As it happens, the skull was originally dubbed Homo rhodesiensis by Arthur Smith Woodard, but is now commonly considered to be H. heidelbergensis or perhaps a close relative. But this isn’t all Atlantis Rising got wrong: the parietal bone opposite the hole is not shattered at all. This appears to be a bit of exaggeration added to the skull’s lore to satisfy the significance-junkies. After all, if someone is to be shot in the head with a rifle, one expects an exit wound. One also expects the shot to kill the individual. Interestingly enough, the hole on the Kabwe skull shows signs of healing, demonstrating beyond doubt that this guy wasn’t dead from the wound. At least not initially. From the Human Origins Program at the Smithsonian Institution website:

The cranium shows evidence of disease and wounds that occurred in the lifetime of this individual. Ten of the upper teeth have cavities, and dental abscesses of the upper jaw are clearly visible in the upper photograph (above the right incisor/canine) and the middle photograph (above the first molar). Additionally, a partially healed wound is visible in the bottom two photographs, above and anterior of the hole for the ear. This wound measured roughly a quarter-inch across, and was made by either a piercing instrument or the tooth of a carnivore. Exactly which is unclear.

The other artifacts mentioned in the Atlantis Rising article included the Ashoka Pillar, the Antikythera “computer,” Egyptian planes, South American jets, crystal skulls, Ica stones, and metal spheroids. Perhap I’ll go into detail on these “artifacts” in future posts.

Paleoanthropology: Multiregional versus Replacement

The multiregional evolution hypothesis asserts that modern humans are the present manifestation of older species of hominids including Homo neanderthalensis and H. erectus. The replacement hypothesis, however, states that modern humans are a new species and that the older species mentioned above were replaced.

In the latter hypothesis, transition of archaic H. sapiens to modern doesn’t occur anywhere in the world except Africa at around 200,000 years ago. Anatomically modern humans then dispersed outward to other regions, replacing other hominid species by out-competing them for resources or by displacing them from environments optimal for their continued survival.
There is, however, a very persistent group of paleoanthropologists who adhere to the multiregional evolution argument, which doesn’t, by the way, imply that there was parallel evolution or multiple origins of modern humans. This theory suggest that genetic exchange explains how differentiation, geographic variation, and evolutionary change within humans occurred.

The arguments have gone back and forth between the two camps for many years, but new research is supporting the multiregional evolution hypothesis. In a recent article by National Geographic , “Neandertals, Modern Humans Interbred, Bone Study Suggests”, Erik Trinkaus, an anthropologist at Washington University in St. Louis, Missouri. comments on a fossil remains found at Petera Muierii (“Cave of the Old Woman”) in Romania, which date to about 30,000 years ago.

While the remains are largely typical of modern humans, they also show some distinctly Neandertal traits, says Trinkaus. […] These telltale skeletal features include the shape of the lower jaw and the back of the skull.

Unfortunately, the National Geographic article doesn’t go into a great amount of detail regarding the cranial and post-cranial morphology of the remains found in Romania, but classic Neanderthal features include a distinct brow ridge, lack of a chin, and occipital bun and their cranial capacities were significantly larger than that of modern humans. Trinkaus does say in the article:

“The only way I can explain the anatomy of these fossils and the fossils from a number of other sites across Europe is that there was a fair amount of interbreeding.”

According to National Geographic, the research is reported in the Proceedings of the National Academy of Sciences , though, I’ve not been able to locate a citation yet to the research article itself. I’m sure this won’t settle the Multiregional vs. Replacement debate, but it certainly is thought provoking.

Hat tips go to Abnormal Interests who set me to looking for the PNAS article and clicking on the National Geographic article with a post of his own on the subject and another to a friend that emailed the PNAS article to me this morning: thanks!

Homo floresiensis Update: Not a Hobbit?

"LB1 is not a normal member of a new species, but an abnormal member of our own," or so concludes Dr. Robert B. Eckhardt, professor of developmental genetics and evolutionary morphology, department of kinesiology, Penn State.

I’ve previously posted about Homo floresiensis (a.k.a. the Hobbit):
New Species or Modern Human? and
Stone Tools of a New Hominid Species?.

Afarensis has also made several posts:
Homo floresiensis: More on Microcephaly
Stone Tools and Homo floresiensis
Tis a Puzzlement: More on Homo floresiensis
The Loom on the Hobbit

And Carl Zimmer’s post, Hobbit as a Monkey? is well worth the read if you are following this topic.

The Eckhardt quote above can be found at this recent Eureka Alert , however.

A research team headed by Teuku Jacob (laboratory of bioanthropology and paleoanthropology, Gadjah Mada University, Indonesia), which included Eckhardt and others, was granted permission to analyze LB1, the nearly complete remains of the individual they now say is mislabeled H. floresiensis. They also had access to the remains of other individuals found at the same site.

The team has published a research article that can be viewed at the Proceedings of the National Academy of Sciences, " Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities. "

In the article, Jacob et al summarize the evidence against a new species as the following:

  1. Demography, Continuity, and Isolation. The contention that a new species, H. floresiensis, evolved in extended isolation, which would require that migration to the island could only have occurred once and in large enough numbers to have provided sufficient genetic diversity to allow a sustained population of a new species in a very short period of time. The evidence of stegadon migration would indicate that humans couldn’t have been restricted to a single migration. Basically, there wasn’t enough resources to support a population large enough to provide enough genetic diversity for the alleged founder group and yet keep them in isolation long enough (tens of thousands of generations).
  2. Neurocranium and Face. None of the features and characters of the LB1 cranium or the two available mandibles are "outside the range for modern humans of the region." Microcephaly provides the explanation for the small cranium and is indicated by the closure of cranial sutures. In addition 10 other examples of microcephalic skeletons are referred to, noting that none their abnormalities are used to establish new species.
  3. Dentition. Premolar crown rotation and other dental characteristics are consistent with modern pygmies in the Liang Bua region.
  4. Postcrania. Abnormality is evident throughout the postcranial skeleton, particularly with the leg bones. CT scans of leg bone cross sections reveals that the cortical bone is thin (~2 mm), abnormal for any primate over 1 meter tall. This and other features indicate that LB1 is anything but robust, as previously described by others. Deltoid tuberosity of the humerous is nearly absent and the difference in width between the subdeltoid and supradeltoid is small, indicative of weak muscle development.

I must say, Jacob et al present a good case for arguing that others were premature in attempting to establish a new species.

And the article is free via open access!

Jacob, T; Indriati, E; Soejono, R.P.; et al (2006). Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities. Proceedings of the National Academy of Sciences, 103 (36), 13421-13426.

Howler Monkeys Part 4: References and Cited Works

I hope if you read this far in this four part series, that you enjoyed reading about one of the most enigmatic New World monkeys. Below is the list of works cited in the previous three parts, but I’m also going to include a few sources that are Internet accessible for those without quick access to the books and journal articles.

Internet Sources

Google Image Results for “howler monkey”

Wikipedia Entry for howler monkey. This link includes some images including the one used to show schizodactyly.

Honolulu Zoo Fact Sheet

The Loudest Animal In the World, an article by Terry Dunn hosted by the Smithsonian National Zoological Park website.

Cited References

Carpenter, C. R. (1934). A Field Study of the Behavior and Social Relations of Howling Monkeys. New York: AMS Press.

Fleagle, J. G. (1999). Primate Adaptation and Evolution, 2nd Ed.. San Diego, CA: Academic Press.

Gilbert, K. A., & Stouffer, P. C. (1989). Use of a ground water source by mantled howler monkeys (Alouatta palliata). Biotropica, 21(4), 380.

Kinzey, W. G. (1997). New World Primates: Ecology, Evolution, and Behavior. New York: Aldine De Gruyter.

Kitchen, D. M. (2004, 19/03). Alpha male black howler monkey responses to loud calls: Effect of numeric odds, male companion behavior and reproductive investment. Animal Behavior, 67, 125-139.

Milton, K. (1980). The Foraging Strategy of Howler Monkeys: A Study in Primate Economics. New York: Columbia University Press.

Pinto. Liliam P., & Setz, E. Z. (2004, December). Diet of Alouatta belzebul discolor in an Amazonian rain forest of Northern Mato Grosso State, Brazil. International Journal of Primatology, 25(6), 1197-1211.

Regan, B. C., Julliot, C., Simmen, B., Viénot, F., Charles-Dominique, P., & Mollon, J. (1998, November). Frugivory and colour vision in Alouatta seniculus, a trichromatic platyrrhine monkey. Vision Research, 38(21), 3321-3327.

Richard-Hansen, C., Vié, J.-C., & de Thoisy, B. (2000). Trnaslocation of red howler monkeys (Alouatta seniculus) in French Guiana. Biological Conservation, 93, 247-253.

Howler Monkeys Part 2: Dietary Needs and Habits

Howler Photo by princessangel

Milton’s Study on and Island in the Panama Canal

Milton studied two groups of mantled howlers on Barro Colorado Island in the Panama Canal (1980) and discovered that while howlers don’t have to pursue their foods, neither can they use a “sit and wait” strategy. Their preference for seasonal foods presents them with a continual problem of locating foods they like. Food location and monitoring was their main reason for travel and the alpha male in her study groups would initiate travel with a “low, almost inaudible, cough (p. 102).” The members of the troop would gather in one area of a tree and move out, single file, in a direction indicated by the alpha male. The troop’s travel through trees was in single file, which suggested to Milton a “goal-oriented” endeavor rather than a phalanx formation as with other primate species that would want to cover as much area as possible in their search for food. She also notes, however, that the single file is less risky because the relatively massive howler monkey is in danger of falling should it grab a branch that is brittle or dead, which breaks. The single file formation could be a method of providing a safe, proven route for the troop and the troop often used the same routes for other travel events, reinforcing this hypothesis.

Recharging the Batteries

In Milton’s study (1980), 90% of all travel events were followed by feeding events. She found that her observed groups traveled 1.23 mean hours per day at a mean distance of 443 meters at a mean rate of 360 meters per hour and she referred to howlers as “travel minimizers.” The howlers slept wherever they happened to find suitable spots at nightfall and at their last feeding location. While feeding, howlers generally orient themselves around 1 or 2 “pivotal” trees, moving to different pivotal trees once depleted.

Milton (1980) reported that, of the Howlers she observed during her Barro Colorado Island study, 91.4% of their feeding time was spent on seasonal foods: young leaves, fruits and flowers. They spent 1.6% of their feeding time on perennial foods or foliage that could be considered mature even though perennial foods were more abundant than seasonal and always available, showing a clear preference for specific foods. In a study along the Teles Pires River in Brazil (Pinto and Setz 2004), red-handed howlers (Alouatta belzebul discolor) were similarly observed to prefer seasonal fruits, leaves and flowers over perennial in which the howlers of the study spent 72-92% of their feeding time on the seasonal foods even though perennial were always available. Kinzey (1997) noted that howlers “are either folivore-frugivores or frugivore-folivores, depending on the population and season (p. 179).” He also indicated, as Milton did, that there are food preferences that influence the decisions of howler foraging strategies and that young leaves are preferred over mature but that there is clear exclusivity correlated to seasons, habitat, species and populations within species. At times, howlers prefer fruits or flowers over leaves, while during the same season but in different habitats, the same species might prefer leaves over fruit. Kinzey cites an unpublished dissertation that revealed the howlers of the study required 15.6% of their diet to consist of protein and that this is a driving force in their food choices.

Couch Potatoes?

The howler diet limits their activity and, indeed, dominates it. On average, howlers spend over 60% of their day resting and traveled mainly to locate or monitor food sources (Milton 1980). Howlers of the Barro Colorado (Milton 1980) and the Teles Pires (Pinto and Setz 2004) both preferred products of species of Ficus: leaves, fruits and flowers. However, they were also noted to feed on other species as well. Milton documented 87 leaf sources, 36 fruit sources, and 25 flower sources in her study of the mantled howler while the red-handed howlers in the Pinto and Setz study consumed leaves from 27 sources, fruits from 35 sources, and flowers from 8 sources. Milton observed to eat some leaf species only once, however, and hypothesized that the monkeys could have been sampling other leaf sources within their habitat and, perhaps, gauging them for palatability and nutritional value. She cited the specialized receptors in rats that can recognize potential nutrient-rich foods, sending information to the central nervous system and suggested that Alouatta may have a similar adaptive function. Howlers also appear able to detoxify secondary compounds in food sources, such as terpene, an unsaturated hydrocarbon found in plants. Other New World primates haven’t developed this function (Milton 1980).

See-Food Diet

Trichromatic primates, which include humans as well as Alouatta, have three specialized cones for color vision (Fleagle 1999, pp. 25-26). In a study of the red howler, in the rainforest of French Guiana, (Regan et al 1998), it was concluded that trichromacy in Alouatta allows howlers to locate and identify fruits among foliage from long distances. Regan et al admitted that, while their results were conclusive with regard to the ability of red howlers to consistently identify specific fruits and that specific fruits were optimally colored, they could not demonstrate whether trichromacy was an evolutionary adaptation to the fruit or whether the fruit colors were adapted to the trichromacy. The did, however, underscore the unknown cause of dichromacy among other Platyrrhines, where there are only two color cones rather than three, thus limiting the ability of dichromats to see certain colors effectively.

Washing it all down? Not for the Howler.

Howlers generally obtain water from their food (Carpenter 1934; Milton 1980; Kinzey 1997; Gilbert and Stouffer 1989), leaves and fruit can contain up to 95% water by weight or from arboreal sources following a rain where the monkeys lick their fingers after wetting them in the runoff (Carpenter 1934). Rarely, howlers have been observed coming to drink at standing ground water sources (Gilbert and Stouffer 1989; Carpenter 1934), but in a very cautious manner. The observation by Gilbert and Stouffer was that the monkeys left the trees one at a time to drink with a male, probably the alpha, standing watch. They hypothesized that the dry conditions of that year imposed a water stress that inhibited growth of new leaves, forcing the howlers to obtain water from other sources.

Howler Monkeys Part 3: Vocalizations

Howler Photo by JeanKearn

Perhaps the most familiar characteristic of the howler monkey are their vocalizations for which they are named. Howlers, both male and female, use their loud, lion-like roars (Fleagle 1999 p150) to advertise their presence and to warn or intimidate intruders (Kitchen 2004). Vocalizations may also provide auditory cues that reveal fighting ability of a group or an individual (Kitchen 2004). Vocal battles may culminate or result in actual physical combat in which an intruder makes an effort to usurp the group’s alpha male. Most howler troops consist of several adult males, but have a single alpha male that mates with the troop’s females, putting any dependent offspring in the alpha’s lineage. The immigrant male that forcibly replaces the group’s alpha can kill the dependent infants of the ousted alpha male (Fleagle 1999, p152; Kitchen 2004, p126). Infanticide of offspring under 9 months old hastens the female’s return to estrus, allowing the immigrant alpha male the opportunity to establish his own lineage according to data that is both circumstantial and observational (Kitchen 2004).

The Influence of Offspring

Kitchen discovered that the presence of small offspring had an influence on the alpha male’s vocal responses in that the alpha was quicker to begin howling, howled more often, and for longer periods when small offspring were present in the group. If the odds were against the alpha, howling was done only when small offspring were present, suggesting that an assessment was made by the monkey regarding the value of winning before escalating the conflict. Kitchen concluded that howling displays are costly with regard to energy, but the benefits outweigh the costs if intruders can be impeded. She also noted that males of small offspring stood their ground and, while did not advance upon aggressors, did not flee, indicating that stationary displays might be a compromise between fight and flight.

Keepin’ it on the ‘Down Low’

Kitchen also observed that howlers didn’t always respond to howling neighbors during natural encounters. This, she reasoned, could be due simply to conservation of energy since the howler’s diet limits activity. In general, howlers spend more than 60% of their day resting (Milton 1980; Kitchen 2004). Kitchen also suggested that the lack of vocal response could be a part of a strategy to remain hidden and quiet not only to conserve energy but to avoid facing superior opponents, which could, in turn, suggest that acoustic characteristics might be present in vocalizations which reveal fighting ability.

Loud calls occur most frequently at dawn and may serve the purpose of announcing a group’s location, establishing territory and distance between groups, and revealing a group’s actual composition. They can also serve the purpose of strengthening pair bonds between mates through “duets.” Vocalizations at night, however, occur at a higher rate than the day and calls have been measured to be as high as 90 dB and below 1 kHz (Kinzey 1997).

Conservation and Protection for the Howler

Howlers are reported to have been preyed on by both the harpy eagle and the jaguar (Kinzey 1997), but their most serious threat is, perhaps, habitat loss due to human activity. The construction of the Petit Saut hydroelectric dam in French Guiana flooded over 365 square kilometers of forest by 1995 destroying the natural habitats of many species, including that of the red howler (Richard-Hansen, Vié, and de Thoisy 2000). The red howlers in the inundated habitat were previously hunted to the point of serious reduction of population and the decision was made to translocate the remaining groups in the region to a new habitat. Though all but one of the translocated groups split up after being released in a new home range, the overall operation was considered a success since many of the distinctive behaviors of individuals within the groups were re-observed following the translocation. Richard-Hansen, Vié and de Thoisy (2000) demonstrated that such translocations were viable in situations of habitat destruction or other conservation needs exist.