Birds form one of six basic animal groups, with the others being amphibians, fish, invertebrates, mammals and reptiles. They are endothermic vertebrates, characterized by feathers, toothless beaked jaws, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. They reproduce by laying of hard-shelled eggs (eggs fertilize inside the female). The fossil record indicates that birds are the last surviving group of dinosaurs. So, they are also termed avian dinosaurs.
Birds (Aves) range in size and weight from the 5 cm (2 in) and 1.6-2 grams bee hummingbird to the 2.75 m (9 ft) and 104-156 kg (229-344 lbs) ostrich. Here are the top 15 largest (by body weight) living bird species.
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Here are the top five largest living fish species (within around 33,100 described species).
But, first of all, what is a fish? At first, it looks like an easy question, but in fact it is not. There are a wide range of animals we call “fish”, so it is not easy to define what makes a fish “a fish”. A general description: “a fish is any member of a paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits” (wikipedia).
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After the extinction of the dinosaurs, approximately 66 million years ago, the rise of mammals begun. There were mammals on earth before that date, but after the Cretaceous–Paleogene (K–Pg) extinction event (a mass extinction of some three-quarters of the plant and animal species on Earth—including all non-avian dinosaurs), mammals took over the medium- to large-sized ecological niches.
Some of them reached enormous sizes, usually they were larger than today’s counterparts (with the exception of whales). Here are some of the largest known prehistoric mammals.
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Like all prehistoric counterparts of today’s animals, the prehistoric cats were usually larger, heavier and more robust than today’s felines. Here are the top five largest prehistoric cats.
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National Geographic grantee Federico Fanti and his research team have unearthed a sea-dwelling crocodylomorph (a teleosaurid) skeleton in southern Tunisia, in the Sahara desert: Machimosaurus rex. It is the world’s largest marine crocodyliform, and was previously unknown to science. It’s length is estimated at more than 30 feet (9.14 meters). The giant was probably weighed three tons.
Continue reading A giant prehistoric crocodile discovered in the Sahara: Machimosaurus rex
Identifying the largest dinosaurs ever lived isn’t an easy task, because it’s very rare to unearth a complete fossil. Furthermore, only a tiny percentage of these amazing animals ever fossilized, and most of these “lucky” bodies will remain buried underground forever. So, we may never know exactly what dinosaur was the biggest (or the tiniest) ever.
Despite this fact, size always has been one of the most interesting aspects of these prehistoric animals. There are extreme variations in their size, from the tiny hummingbirds, which can weigh as little as three grams, to the titanosaurs, which could weigh as much as 70 tonnes, or even more.
Here are some of the largest dinosaurs ever lived.
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Our old planet, the Earth is 4.54 billion years old. In fact, the human mind can no longer make any sense of the large numbers like that. Numbers like 1, 2, 14, 20, 50 are all quantities that we encounter quite frequently in our daily lives. And out brain evolved to conceptualize numbers like that: our ancestors saw two lions; they hunted five deer in one hunting party, the population of their tribe was 20, etc… But when the numbers are getting big, i.e. 1,000; 10,000… the problem begins: these numbers become increasingly difficult to conceptualize. Now what happens when we try to conceptualize quantities like billions, like the Earth’s age? We can’t actually rationalize the immensity of such a big number. Because we haven’t a model of 4.54 billion that’s been compressed into something recognizable to the human mind.
Continue reading If Earth’s life time was the distance from Los Angeles to New York City
Previously, I published a post about the largest crocodiles ever recorded. All sizes in that post were recorded in the recent times. The crocs listed were large, yes, but not as big as most people think. But in the prehistoric ages, some animals were much bigger than today’s counterparts – including crocodiles. So, what was the World’s biggest crocodile ever lived? Here are the top six candidates.
Continue reading World’s top 6 biggest prehistoric crocodiles ever lived