Teratornis
Encyclopedia
Teratornis merriami was a huge North America
n teratorn
, with a wingspan of around 3.5 to 3.8 meters (11 to 12 feet) and a wing area of 17.5 square meters, standing an estimated 75 cm tall and weighing about 15 kg. It was somewhat larger than the extant Andean Condor
and nearly two double the weight of the California Condor
. A closely related genus, Aiolornis
, was about 40% larger and lived at an earlier time; it was formerly known as Teratornis incredibilis, but is distinct enough to be placed in its own genus.
T. merriami is the best-known of the teratorns. A large number of fossil
and subfossil
bones, representing more than 100 individuals, have been found in locations in California
, southern Nevada
, Arizona
, and Florida
, though most are from the Californian La Brea Tar Pits
. All remains but one Early Pleistocene
partial skeleton from the Leisey Shell Pit near Charlotte Harbor, Florida
(which may represent a different species or a subspecies) date from the Late Pleistocene
, with the youngest remains dating from the Pleistocene
-Holocene
boundary.
The finger bones are fused as in all modern birds; however, part of the index finger forms a shelf which aided in bearing the load of long and stout primaries, which enabled the bird to utilize strong upcurrents. The legs were similar to an Andean Condor's, but stouter, and the feet were able to hold prey items for tearing off pieces, but not able to exert a very forceful grip such as in birds of prey. Its wing loading
was not much larger than a Californian Condor's, and Merriam's Teratorn should have been able to take off by simply jumping and beating its wings under most circumstances. (Campbell & Tonni, 1983). Indeed, it seems to have been better adapted for that than for utilizing a short run into the wind from an elevated location as condors do, as its legs are proportionally smaller and its stride less than in condors (Fisher, 1945).
would have been fed on in a manner similar to that of condors or vulture
s. The large number of finds in the La Brea Tar Pits
were usually considered to be from teratorns which were attracted by Pleistocene megafauna
that became stuck in the viscous asphalt
trying to drink from pools of water that gathered on the surface and died, with the teratorns subsequently falling victim to the sticky deposits too. Merriam's Teratorn probably played an important role in opening up the body cavities of carcasses for smaller birds like eagle
s and raven
s which are also known to have frequented the locality, as mammal
ian predators, being unable to fly, could hardly reach most carcasses without getting mired in the asphalt themselves.
However, there were also true vultures
present in the area at that time, and unlike them, T. merriami was also well adapted to hunt for smaller animals which are also known to have utilized the pools. Analysis of the skull and bill shapes suggests that fish may have constituted a major part of its diet (Hertel, 1995). Taking into account the strong legs, stout claws, and a gripping power not quite as developed as in eagles, it is rather likely that Merriam's Teratorn would have hunted for aquatic prey in the manner of an osprey
, which also provides a neat explanation of how such large numbers of powerful, well-flying birds could have become stuck in the asphalt.
The species probably became extinct
as the climatic shifts at the end of the last ice age
led to widespread ecological alterations and prey scarcity, exacerbated by human hunting and increasing influence on habitat; generally, most large land animals disappeared and the altered precipitation patterns seriously affected populations of aquatic vertebrates. Despite being a better hunter than the Californian Condor, it still was inferior as a predator of small prey to hawk
s and eagle
s. The higher population density and more flexible diet of the condor probably ensured that it survived, while T. merriami did not. Recent isotopic studies suggest that the California Condor was able to survive the extinction of the megafauna because it also scavenged dead marine mammals off the Pacific Coast. The teratorn relied more heavily upon the carrion of land mammals and therefore could not survive their extinction.
s show, the bird was possibly hunted, and probably large and possibly predatory enough to consider human infants food.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n teratorn
Teratornithidae
Teratorns were very large birds of prey that lived in North and South America from Miocene to Pleistocene. They include some of the largest known flying birds. So far, at least four species have been identified:*Teratornis merriami . This is by far the best-known species...
, with a wingspan of around 3.5 to 3.8 meters (11 to 12 feet) and a wing area of 17.5 square meters, standing an estimated 75 cm tall and weighing about 15 kg. It was somewhat larger than the extant Andean Condor
Andean Condor
The Andean Condor is a species of South American bird in the New World vulture family Cathartidae and is the only member of the genus Vultur...
and nearly two double the weight of the California Condor
California Condor
The California Condor is a New World vulture, the largest North American land bird. Currently, this condor inhabits only the Grand Canyon area, Zion National Park, and coastal mountains of central and southern California and northern Baja California...
. A closely related genus, Aiolornis
Aiolornis
Aiolornis incredibilis , of the teratorn family, was the largest known North American flight-capable bird, with a wingspan of up to 17 feet and a huge, deep, powerful bill. A. incredibilis presumably became extinct at the same time as the other megafauna in North America...
, was about 40% larger and lived at an earlier time; it was formerly known as Teratornis incredibilis, but is distinct enough to be placed in its own genus.
Physical characteristics
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
and subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
bones, representing more than 100 individuals, have been found in locations in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, southern Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
, Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, and Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, though most are from the Californian La Brea Tar Pits
La Brea Tar Pits
The La Brea Tar Pits are a cluster of tar pits around which Hancock Park was formed, in the urban heart of Los Angeles. Asphaltum or tar has seeped up from the ground in this area for tens of thousands of years. The tar is often covered with water...
. All remains but one Early Pleistocene
Early Pleistocene
Calabrian is a subdivision of the Pleistocene Epoch of the Geologic time scale. ~1.8 Ma.—781,000 years ago ± 5,000 years, a period of ~.The end of the stage is defined by the last magnetic pole reversal and plunge in to an ice age and global drying possibly colder and drier than the late Miocene ...
partial skeleton from the Leisey Shell Pit near Charlotte Harbor, Florida
Charlotte Harbor, Florida
Charlotte Harbor is a census-designated place in Charlotte County, Florida, United States. The population was 3,647 at the 2000 census. It is part of the Punta Gorda Metropolitan Statistical Area.-Geography:...
(which may represent a different species or a subspecies) date from the Late Pleistocene
Late Pleistocene
The Late Pleistocene is a stage of the Pleistocene Epoch. The beginning of the stage is defined by the base of the Eemian interglacial phase before the final glacial episode of the Pleistocene 126,000 ± 5,000 years ago. The end of the stage is defined exactly at 10,000 Carbon-14 years BP...
, with the youngest remains dating from the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
-Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
boundary.
The finger bones are fused as in all modern birds; however, part of the index finger forms a shelf which aided in bearing the load of long and stout primaries, which enabled the bird to utilize strong upcurrents. The legs were similar to an Andean Condor's, but stouter, and the feet were able to hold prey items for tearing off pieces, but not able to exert a very forceful grip such as in birds of prey. Its wing loading
Wing loading
In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. The faster an aircraft flies, the more lift is produced by each unit area of wing, so a smaller wing can carry the same weight in level flight, operating at a higher wing loading. Correspondingly,...
was not much larger than a Californian Condor's, and Merriam's Teratorn should have been able to take off by simply jumping and beating its wings under most circumstances. (Campbell & Tonni, 1983). Indeed, it seems to have been better adapted for that than for utilizing a short run into the wind from an elevated location as condors do, as its legs are proportionally smaller and its stride less than in condors (Fisher, 1945).
Ecology and extinction
T. merriami generally lived in a manner similar to condors, although its larger bill suggests that it was a more active predator. Prey up to the size of a small rabbit would probably have been swallowed more or less whole, while carrionCarrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
would have been fed on in a manner similar to that of condors or vulture
Vulture
Vulture is the name given to two groups of convergently evolved scavenging birds, the New World Vultures including the well-known Californian and Andean Condors, and the Old World Vultures including the birds which are seen scavenging on carcasses of dead animals on African plains...
s. The large number of finds in the La Brea Tar Pits
La Brea Tar Pits
The La Brea Tar Pits are a cluster of tar pits around which Hancock Park was formed, in the urban heart of Los Angeles. Asphaltum or tar has seeped up from the ground in this area for tens of thousands of years. The tar is often covered with water...
were usually considered to be from teratorns which were attracted by Pleistocene megafauna
Pleistocene megafauna
Pleistocene megafauna is the set of species of large animals — mammals, birds and reptiles — that lived on Earth during the Pleistocene epoch and became extinct in a Quaternary extinction event. These species appear to have died off as humans expanded out of Africa and southern Asia,...
that became stuck in the viscous asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
trying to drink from pools of water that gathered on the surface and died, with the teratorns subsequently falling victim to the sticky deposits too. Merriam's Teratorn probably played an important role in opening up the body cavities of carcasses for smaller birds like eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
s and raven
Raven
Raven is the common name given to several larger-bodied members of the genus Corvus—but in Europe and North America the Common Raven is normally implied...
s which are also known to have frequented the locality, as mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian predators, being unable to fly, could hardly reach most carcasses without getting mired in the asphalt themselves.
However, there were also true vultures
Old World vulture
Old World vultures belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.Old World vultures are not closely related to the superficially similar New World vultures and condors, and do not share that group's good sense of smell. The similarities between the two...
present in the area at that time, and unlike them, T. merriami was also well adapted to hunt for smaller animals which are also known to have utilized the pools. Analysis of the skull and bill shapes suggests that fish may have constituted a major part of its diet (Hertel, 1995). Taking into account the strong legs, stout claws, and a gripping power not quite as developed as in eagles, it is rather likely that Merriam's Teratorn would have hunted for aquatic prey in the manner of an osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...
, which also provides a neat explanation of how such large numbers of powerful, well-flying birds could have become stuck in the asphalt.
The species probably became extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
as the climatic shifts at the end of the last ice age
Wisconsin glaciation
The last glacial period was the most recent glacial period within the current ice age occurring during the last years of the Pleistocene, from approximately 110,000 to 10,000 years ago....
led to widespread ecological alterations and prey scarcity, exacerbated by human hunting and increasing influence on habitat; generally, most large land animals disappeared and the altered precipitation patterns seriously affected populations of aquatic vertebrates. Despite being a better hunter than the Californian Condor, it still was inferior as a predator of small prey to hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
s and eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
s. The higher population density and more flexible diet of the condor probably ensured that it survived, while T. merriami did not. Recent isotopic studies suggest that the California Condor was able to survive the extinction of the megafauna because it also scavenged dead marine mammals off the Pacific Coast. The teratorn relied more heavily upon the carrion of land mammals and therefore could not survive their extinction.
Interaction with humans
Bones found in Amerindian middenMidden
A midden, is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, vermin, shells, sherds, lithics , and other artifacts and ecofacts associated with past human occupation...
s show, the bird was possibly hunted, and probably large and possibly predatory enough to consider human infants food.