10 Weirdest Dinosaurs: #1 Therizinosaurus

Not all dinosaurs (or archosaurs, or pterosaurs) sported the same plain-vanilla body plans. Some of these creatures stood out even by the bizarre standards of the Mesozoic Era, with strange adaptations that continue to puzzle paleontologists to the present day.

Kind of like Big Bird crossed with Count Dracula, Therizinosaurus was a large type of theropod dinosaur known as a therizinosaur, with a squat trunk, a long neck, a tiny head, and a trio of three-foot-long claws on each of its hands (hence its name, Greek for "reaping lizard"). Despite its fearsome appearance (which may or may not have included brightly colored feathers), Therizinosaurus was a strict vegetarian, or at worst an omnivore.

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How Feathered Dinosaurs Learned to Fly

The Evolution of Feathered Dinosaurs into Birds

 

As little as 50 years ago, the idea that birds descended from dinosaurs seemed completely ridiculous--after all, birds are small, light, fluttery creatures, while dinosaurs were huge, plodding, and distinctly unaerodynamic. But as the evidence--small dinosaurs possessing feathers, beaks, and other birdlike characteristics--began to mount, the connection between dinosaurs and birds became apparent to scientists and the general public. Today, it's the rare paleontologist who disputes the descent of birds from dinosaurs, though there are some who try.

This doesn’t mean, though, that all the technical aspects of the dinosaur/bird transition have been settled once and for all. Researchers still disagree about which dinosaurs were most closely related to modern birds, whether terrestrial dinosaurs sported aerodynamic or strictly ornamental feathers, and--perhaps most contentiously of all--how these reptilian proto-birds managed to achieve the huge evolutionary leap into powered flight.

Theory #1: Feathered Dinosaurs Took a Running Leap

Extrapolating backward from the behavior of modern birds, like ostriches, it's reasonable to infer that the small- to medium-sized, two-legged theropods of the Cretaceous period (notably the ornithomimids, or "bird mimics," but other feathered theropods as well, including raptors and possibly even small tyrannosaurs) could attain top running speeds of 30 or 40 miles per hour. As these theropods ran (either chasing down prey or trying to outrun bigger carnivores), their coat of insulating feathers gave them a slight aerodynamic "bounce," helping them land their next meal or live another day. Since well-fed dinosaurs, or those that avoided being eaten, produced more offspring, the evolutionary trend would be toward larger feathers, which provided more "lift."

From there, the theory goes, it would only have been a short step to taking actual flight for brief periods of time. At this point, though, it's important to realize what the phrase "short time" means in an evolutionary context. There wasn't a single defining moment when a small, feathered theropod accidentally ran off the side of a cliff and took flight like a modern bird. Rather, you have to picture this process happening gradually over the course of millions of years--and with multiple theropods, not any specific genus.

In the excellent Nova episode The Four-Winged Dinosaur (about the specimen of Microraptor that had recently been discovered in China), a scientist is quoted to the effect that the hatchlings of modern birds recapitulate their evolutionary heritage. That is, though they're still unable to fly, they can jump farther, and scuttle up inclined surfaces, with the aerodynamic lift provided by their feathers--the same advantages that may have been enjoyed by Cretaceous theropods.

Theory #2: Feathered Dinosaurs Fell Out of Trees

Birds aren't the only animals alive today whose behavior can be extrapolated back to extinct dinosaurs. Flying squirrels glide across forests by leaping off the tall branches of trees and spreading the flaps of skin attached to their arms and legs. They’re not capable of powered flight, of course, but they can glide for impressive distances, up to two-thirds of the length of a football field for some species.

Conceivably, some species of feathered theropod might have lived high up in trees (this would entail their having a relatively small size and the ability to climb). These feathered dinosaurs might then have followed the same evolutionary path as flying squirrels, gliding for longer and longer distances as their feathers slowly evolved to the optimum shape and configuration. At some point, the evolutionary innovation of flappable wings would have allowed them to take to the air for indefinite periods of time. Voila - the first prehistoric birds!

The main problem with this "arboreal" theory of flight, as it’s called, is that it's easier to imagine powered flight evolving in the ground-up alternative (picture a terrified dinosaur desperately flapping its vestigial wings to try to escape a larger carnivore) than as a result of tree-to-tree gliding. Also, despite millions of years of evolution, no flying squirrel (with the exception of Bullwinkle's pal Rocky) has managed to achieve powered flight--although, to be fair, bats certainly have.

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Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Pterousaurs - Flying Dinosaurs!

Pteranodon, the most famous of all pterosaurs (American Museum of Natural History)

Pterosaurs ("winged lizards") hold a special place in the history of life on earth: they were the first creatures, other than insects, to successfully populate the skies. The evolution of pterosaurs roughly paralleled that of their terrestrial cousins, the dinosaurs.

Paleontologists have found indisputable proof that modern birds are descended not from pterosaurs, but from small, feathered, land-bound dinosaurs (in fact, if you could somehow compare the DNA of a pigeon, a Tyrannosaurus Rex and a Pteranodon, the first two would be more closely related to each other than either would be to the third). This is an example of what biologists call convergent evolution: nature has a way of finding the same solutions (wings, hollow bones, etc.) to the same problem (how to fly). Learn More About Pterousaurs Here
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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Shuvuuia

Late Cretaceous (85-75 million years ago)

Size and Weight:About 2 feet long and 6 pounds

Diet:Insects and small animals

Distinguishing Characteristics:Small, birdlike head; dinosaur-like forelimbs
 

Shuvuuia is one of those ancient dino-birds that gives paleontologists fits, seeming to be composed of an equal number of bird-like and dinosaur-like characteristics. Its head, for example, was distinctly birdlike, as were its long legs and three-toed feet, but its too-short arms call to mind the stunted limbs of bipedal theropods like Tyrannosaurus Rex. Lately, the consensus seems to be that the almost certainly feathered Shuvuuia was closer to a dinosaur than to a prehistoric bird, but the issue may never be settled conclusively.

By the way, Shuvuuia also stands out for being one of the few dinosaurs (or prehistoric birds) whose name isn't derived from Greek roots--"shuvuu" is the word for bird in Mongolia, where Shuvuuia's fossils were first discovered.






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Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Dinosaurs (almost certainly) evolved into birds.

Mononykus (Pavel Riha)

Not every paleontologist is convinced, and there are some alternate (albeit not widely accepted) theories. But the bulk of the evidence points to modern birds having evolved from small, feathered, theropod dinosaurs during the late Jurassic and Cretaceous periods. Bear in mind, though, that this evolutionary process may have happened more than once, and that there were definitely some "dead ends" along the way (witness the feathered, four-winged Microraptor, which has left no living descendants).

Part of the reason so many ordinary people doubt the evolutionary link between feathered dinosaurs and birds is because when they think of the word "dinosaur," they picture enormous beasts like Brachiosaurus and Tyrannosaurus Rex, and when they think of the word "bird," they picture harmless, rodent-sized pigeons and robins (and perhaps the occasional eagle or penguin).

Closer to the Jurassic and Cretaceous periods, though, the visual referents are a lot different. For decades, paleontologists have been digging up small, birdlike theropods (the same family of two-legged dinosaurs that includes tyrannosaurs and raptors) bearing unmistakable evidence of feathers, wishbones, and other bits of avian anatomy. Unlike larger dinosaurs, these smaller theropods tend to be unusually well-preserved, and many such fossils have been found completely intact (which is more than can be said for the average sauropod).
Feathered Dinosaurs, Birds and Evolution

What do these fossils tell us about the evolution of prehistoric birds from dinosaurs? Well, for starters, it's impossible to pin down a single "missing link" between these two types of animals. For a while, scientists believed the 150-million-year-old Archaeopteryx was the indisputable transitional form, but it's still not clear if this was a true bird (as some experts claim) or a very small, and not very aerodynamic, theropod dinosaur. (In fact, a new study claims that the feathers of Archaeopteryx weren't strong enough to sustain extended bursts of flight.)

The problem is, the subsequent discovery of other small, feathered dinosaurs that lived at the same time as Archaeopteryx--such as Epidendrosaurus and Pedopenna--has muddied the picture considerably, and there's no ruling out the possibility that future paleontologists will unearth dino-birds from as far back as the Triassic period. In addition, it's far from clear that all these feathered theropods were closely related: evolution has a way of repeating its jokes, and feathers (and wishbones) may well have evolved multiple times.

To show how tricky this issue is, here's the standard picture of bird evolution: small, running theropods (for the sake of argument, let's say raptors) evolved feathers as a way of keeping warm and attracting mates. As these feathers grew larger and more ornate, they provided an unexpected bonus: a split-second of extra "lift" when their owner pounced on prey or ran away from larger predators. Multiply this scenario by countless generations, and you have a solid theory for the origin of avian flight.

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Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Fossils That Changed Dinosaur Brachylophosaurus (2000)

Restoration

Only three complete fossils of the hadrosaur, or duck-billed dinosaur, Brachylophosaurus have ever been found, but they're so amazingly well-preserved that (as paleontologists often do) they were immediately given nicknames: Elvis, Leonardo and Roberta. (The same research team also found a fourth, incomplete fossil of a juvenile, which they dubbed Peanut.)

Leonardo had a birdlike crop on its neck (presumably to aid in digestion) as well as different-sized scales on different parts of its body, among other unique anatomical features.
 
Although it's named for the unusually short crest on its head (short, that is, for a hadrosaur), Brachylophosaurus stood out more for its thick, downward-turning beak, which some paleontologists take as evidence that the males of this genus head-butted one another for the attention of females.

Notable Feathered Dinosaurs: Scansoriopteryx

Scansoriopteryx (Greek for "climbing wing"); pronounced SCAN-sore-ee-OP-ter-ix

Habitat:
Woodlands of Asia

Historical Period:
Early Cretaceous (130-125 million years ago

Size and Weight:
About one foot long and one pound

Diet:
Insects

Distinguishing Characteristics:
Small size; extended claws on each hand

About Scansoriopteryx:

Like the feathered theropod to which it's most closely related--Epidendrosaurus--Scansoriopteryx is thought to have spent most of its life high up in trees, where it poked out grubs from underneath bark with its unusually long middle fingers. However, it's not clear if this dino-bird was covered with feathers, and it appears to have been incapable of flight. So far, this genus is known only by the fossil of a single juvenile; future discoveries should shed further light on its appearance and behavior.

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Rahonavis

Rahonavis (Greek for "cloud bird"); pronounced rah-hoe-NAY-viss
 
Habitat:
Woodlands of Madagascar

Historical Period:
Late Cretaceous (75 million years ago)

Size and Weight:
About one foot long and one pound

Diet:
Probably insects

Distinguishing Characteristics:
Small size; feathers; single curved claw on each foot

About Rahonavis:

Rahonavis is one of those creatures that triggers enduring feuds among paleontologists. When it was first discovered (an incomplete skeleton unearthed in Madagascar in 1995), researchers assumed it was a type of bird, but further study showed certain traits common to dromaeosaurs (better known to the general public as raptors). Like such undisputed raptors as Velociraptor and Deinonychus, Rahonavis had a single huge claw on each hind foot, as well as other raptor-like features.

What is the current thinking about Rahonavis? Most scientists agree that raptors counted among the early ancestors of birds, meaning that Rahonavis might be a "missing link" between these two families. The trouble is, it wouldn't be the only such missing link; dinosaurs may have made the evolutionary transition to flight multiple times, and only one of these lineages went on to spawn modern birds.


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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Protarchaeopteryx

Protarchaeopteryx (Greek for "before Archaeopteryx"); pronounced PRO-tar-kay-OP-ter-ix
 

Habitat:
Woodlands of Asia

Historical Period:
Early Cretaceous (130-125 million years ago)

Size and Weight:
About two feet long and a few pounds

Diet:
Probably omnivorous

Distinguishing Characteristics:
Small size; feathers on arms and tail

About Protarchaeopteryx:

Some dinosaur names make more sense than others. A good example is Protarchaeopteryx, which translates as "before Archaeopteryx," even though this birdlike dinosaur lived tens of millions of years after its more famous ancestor. In this case, the "pro" in the name refers to Protarchaeopteryx's supposedly less advanced features; this dino-bird seems to have been considerably less aerodynamic than Archaeopteryx, and was almost certainly incapable of flight.

If it couldn't fly, why did Protarchaeopteryx have feathers? As with other small theropods, this dinosaur’s arm and tail feathers likely evolved as a way of attracting mates, and may (secondarily) have given it some "lift" if it had to make a sudden, running leap away from larger predators.

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Pedopenna

Pedopenna (Greek for "feathered foot"); pronounced PED-oh-PEN-ah

Habitat:
Woodlands of Asia

Historical Period:
Late Jurassic (150 million years ago)

Size and Weight:
About 3 feet long and 5-10 pounds

Diet:
Probably omnivorous
Distinguishing Characteristics:
Long legs; long claws on hands; feathers

About Pedopenna:

For the past 25 years or so, paleontologists have driven themselves crazy trying to figure out where the dinosaur evolutionary tree ends and the bird evolutionary tree begins. A case study in this ongoing state of confusion is Pedopenna, a tiny, birdlike theropod that was contemporary with two other famous Jurassic dino-birds, Archaeopteryx and Epidendrosaurus. Pedopenna clearly had many birdlike features, and may have been capable of climbing (or fluttering) into trees and hopping from branch to branch. Like another early dino-bird, Microraptor, Pedopenna may have sported primitive wings on both its arms and its legs.

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Oviraptor

Oviraptor (Greek for "egg thief"); pronounced OH-vee-rap-tore
 
Habitat:
Deserts of Asia
 
Historical Period:
Late Cretaceous (85-75 million years ago)
 
Size and Weight:
About 8 feet long and 75 pounds
 
Diet:
Probably meat
 
Distinguishing Characteristics:
Sharp, toothless beak; probably feathers
 
About Oviraptor:

Talk about a bum rap: when the first fossil of Oviraptor was unearthed, sitting atop a clutch of fossilized eggs, the eggs were thought to belong to an entirely different kind of dinosaur, Protoceratops (specimens of which had been found in the immediate vicinity). Naturally, it was assumed this new specimen had stolen the eggs, hence its name, Greek for "egg thief." (See 10 Facts About Oviraptor and a gallery of Oviraptor pictures.)

Although it's still stuck with its inaccurate name, Oviraptor has since been completely vindicated. Paleontologists now believe that the "guilty" specimen had actually been brooding its own eggs, and earned its notoriety simply by being a good mother (or possibly a good father, since males of the species could conceivably have taken part in child-rearing).

Beyond this little snafu, Oviraptor was one of the most birdlike of all dinosaurs, with a sharp, toothless beak and (probably) a coat of feathers. This theropod didn't have wings, but it seems to have been a short step away (in evolutionary terms) from the first flying birds. (By the way, confusingly enough, Oviraptor doesn't technically count as a true raptor, the breed of dinosaurs most famously represented by Deinonychus and Velociraptor.)

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Nomingia

Historical Period: Late Cretaceous (70-65 million years ago)

Size and Weight: About 6 feet long and 25 pounds

Diet: Probably omnivorous

Distinguishing Characteristics :Long legs; clawed hands; fan on end of tail

About Nomingia:

In most cases, the similarity between small theropod dinosaurs and birds is limited to their size, posture, and feather coats. Nomingia took its birdlike attributes one step further: this is the first dinosaur ever discovered to have sported a pygostyle, that is, a fused structure on the end of its tail that supported a fan of feathers. (All birds have pygostyles, though some species' displays are more garish than others, as witness the famous peacock.)

Despite its avian features, Nomingia was clearly more on the dinosaur than on the bird end of the evolutionary spectrum. It's likely that this dino-bird used its pygostyle-supported fan as a way of attracting mates--the same way a male peacock flashes its tail feathers to reel in available females.

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Mononykus

Name:

Mononykus (Greek for "single claw"); pronounced MON-oh-NYE-cuss

Habitat:

Plains of Asia

Historical Period:

Late Cretaceous (80-70 million years ago)

Size and Weight:

About 3 feet long and 10 pounds

Diet:

Insects

Distinguishing Characteristics:

Long legs; long claws on hands

About Mononykus:

More often than not, paleontologists can infer a dinosaur's behavior from its anatomy. That's the case with Mononykus, whose small size, long legs, and long, curved claws point to it being an insectivore that spent its day clawing at the Cretaceous equivalent of termite mounds. Like other small theropods, Mononykus was probably covered in feathers, and represented an intermediate stage in the evolution of dinosaurs into birds.

By the way, you may notice that the spelling of Mononykus isn't quite orthodox by Greek standards. That's because its original name, Mononychus, turned out to have been preoccupied by a genus of beetle, so paleontologists had to get creative. (At least Mononykus was given a name: discovered way back in 1923, its fossil languished in storage for over 60 years, classified as belonging to an "unidentified bird-like dinosaur.")

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Notable Feathered Dinosaurs: Microraptor

Microraptor (Greek for "small thief"); pronounced MY-crow-rap-tore

Habitat:

Woodlands of Asia

Historical Period:

Early Cretaceous (130-125 million years ago)

Size and Weight:

About 2 feet long and 3-4 pounds

Diet:

Probably insects

Distinguishing Characteristics:

Tiny size; primitive feathers; wings on arms and legs

About Microraptor:

Probably because it was so small, Microraptor fossilized unusually well--paleontologists in China have unearthed about two dozen more-or-less complete specimens of this tiny, feathered raptor of the early Cretaceous period, complete with traces of internal organs and primitive feathers.

The most spectacular fact about Microraptor is that it had not one, but two, sets of primitive wings--one on its forearms (similar to other birdlike Dinosaurs, like Archeopteryx,), and one on its hind legs. This formidable feathered arsenal notwithstanding, scientists believe Microraptor was, at best, an occasional glider, much like a flying squirrel--and probably spent most of its life high up in the branches of trees. (A recent study has shown that the feathers of Microraptor were black and glossy, and likely evolved more as a way to attract mates than to fly the short distances between trees.)

This leads to the important question: was Microraptor a crucial "missing link" in the gradual evolution of  dinosaurs into birds, or did it represent a four-winged experiment that (literally) never quite got off the ground? The answer may await future fossil discoveries, but the lack of any four-winged birds living today should give you an important clue.

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Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

The Evolution of Birds, from Archaeopteryx to the Passenger Pigeon

Titanis (Dmitri Bogdanov)

To many avid readers, Titanis will be familiar as the predatory bird in James Robert Smith's best-selling novel (and soon-to-be-movie) The Flock. This prehistoric bird could certainly wreak its share of mayhem: at eight feet tall and 300 pounds (give or take a few inches and pounds for possible sexually dimorphic differences between males and females), Titanis closely resembled its theropod dinosaur forebears, especially its puny arms with long-taloned, grasping hands.

As scary as it was, though, Titanis wasn't the most dangerous hunting bird of ancient times: in fact, it was a late, North American descendant of a race of South American carnivores, the phorusrachids (typified by Phorusrhacos, also known as the Terror Bird), which attained comparable sizes. By the early Pleistocene epoch, about two million years ago, Titanis had managed to penetrate as far north as Texas and southern Florida, the latter of which is The Flock's modern-day setting.

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

The Evolution of Birds, from Archaeopteryx to the Passenger Pigeon

 

The Thunder Bird, Dromornis (Nobu Tamura)

Perhaps for tourism purposes, Australia has been doing its best to promote the Thunder Bird as the largest prehistoric bird that ever lived, proposing an upper-bound weight for adults of a full half a ton (which would vault Dromornis over Aepyornis in the power ratings) and suggesting that it was even taller than the Giant Moa of New Zealand. Those may be overstatements, but the fact remains that Dromornis was a huge bird, surprisingly not related as much to modern Australian ostriches as to smaller ducks and geese.

Unlike these other giant birds of prehistoric times, which (because of their lack of natural defenses) succumbed to hunting by early human settlers, the Thunder Bird seems to have gone extinct all on its own--perhaps because of climatic changes during the Pliocene epoch that impacted its presumed herbivorous diet.

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

The Evolution of Birds, from Archaeopteryx to the Passenger Pigeon

Kelenken (Wikimedia Commons)

A close relative of Phorusrhacos--the poster genus for the family of extinct feathered carnivores known as "terror birds"--Kelenken is known only from the remains of a single, oversized skull and a handful of foot bones described in 2007. That's enough for paleontologists to have reconstructed this prehistoric bird as a mid-sized, flightless carnivore of the mid-Miocene forests of Patagonia, although it's as yet unknown why Kelenken had such a huge head and beak (probably it was another means to intimidate the mammalian megafauna of prehistoric South America).

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

The Evolution of Birds, from Archaeopteryx to the Passenger Pigeon

Terror Bird: Adalgalornis

Andalgalornis (John Conway)

As "terror birds"--the oversized, flightless apex predators of Miocene and Pliocene South America--go, Andalgalornis isn't quite as well known as Phorusrhacos or Kelenken. However, you can expect to hear more about this once-obscure predator, because a recent study about the hunting habits of terror birds employed Andalgalornis as its poster genus. It seems that Andalgalornis wielded its large, heavy, pointed beak like a hatchet, repeatedly closing in on prey, inflicting deep wounds with quick stabbing motions, then withdrawing to a safe distance as its unfortunate victim bled to death. What Andalgalornis (and other terror birds) specifically did not do was grasp prey in its jaws and shake it back and forth, which would have placed undue strain on its skeletal structure.


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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Flying Dinosaurs - Dorygnathus

Dorygnathus (Dmitri Bogdanov)

With its long tail and narrow wings, Dorygnathus was a good example of what paleontologists call a "rhamphorhynchoid" pterosaur.

Rhamphorhynchoids have been found almost exclusively in western Europe, though it's not clear if this is because they were confined to this geographical location or if conditions in early Jurassic Europe happened to be well-suited for fossil preservation.

The most notable feature of Dorygnathus was its long, intermeshing front teeth, which it almost certainly used to snag fish off the surface of the water and hold them firmly in its mouth. Although the fossil specimens discovered so far have been fairly small, as pterosaurs go, there's some speculation that adults of the species may have grown throughout their lives and attained wingspans of five or six feet.

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Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).

Flying Dinosaurs - Eudimorphodon

Although it's not nearly as well known as others of its kind, Eudimorphodon holds an important place in paleontology as one of the earliest pterosaurs: this tiny, winged reptile hopped around the shores of Europe a whopping 210 million years ago, during the late Triassic period. Eudimorphodon possessed the wing structure--forelimbs embedded in an extended flap of skin--characteristic of all pterosaurs, as well as a diamond-shaped appendage at the end of its tail that probably helped it to steer or to adjust its course in mid-air. (By the way, despite its name, Eudimorphodon wasn't particularly closely related to Dimorphodon, beyond the fact that they were both pterosaurs.)

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Check out Bob's Dinosaur Blog !

Bob Strauss is a freelance writer and book author; one of his specialties is explaining scientific concepts and discoveries to both a lay and professional audience.

Bob Strauss is the author of two best-selling question-and-answer books that range across the expanse of science, biology, history and culture: The Big Book of What, How and Why (Main Street, 2005) and Who Knew? Hundreds & Hundreds of Questions & Answers for Curious Minds (Sterling Innovation, 2007).