His theory boils down to this: In the thigh bone of animals, there are tiny holes, known as nutrient foramen, that distribute blood to the bone cells.  In highly active animals like mammals, these holes are relatively large because their bones require more blood keep them healthy.  In less active animals like reptiles, the holes are relatively small.

Measuring the nutrient foramen of a ceratopsian dinosaur, Centrosaurus apertus.
Photo by Dr Donald Henderson, Curator of Dinosaurs from the Royal Tyrrell Museum in Alberta, Canada.

Sarah Smith, a student of Professor Seymour, measured holes in the bones of a range of mammals, from mice to elephants, and reptiles from lizards to crocodiles using specimens from Australian museums.  With the data in tow and comparisons made to the size of the holes, the size of the body, and the animal’s metabolic rate, Seymour determined that the “sizes of the holes were related closely to the maximum metabolic rates during peak movement in mammals and reptiles. The holes found in mammals were about 10 times larger than those in reptiles.”

Museum curators from Canada and Germany then collected data on the holes found in dinosaur fossil bones in their collections.  The specimens were from a wide range of dinosaurs from bipedal and quadrupedal carnivores and herbivores, large and small.

Seymour explained their findings:

“On a relative comparison to eliminate the differences in body size, all of the dinosaurs had holes in their thigh bones larger than those of mammals. The dinosaurs appeared to be even more active than the mammals.  We certainly didn’t expect to see that.  These results provide additional weight to theories that dinosaurs were warm-blooded and highly active creatures, rather than cold-blooded and sluggish.”

To learn more, see Seymour’s article, “Blood flow to long bones  indicates activity metabolism in mammals, reptiles and dinosaurs”.

Israel’s “Lifting Door” Spider
With a leg span of 14 cm (5.5 in.), a new spider found in the dune of the Sands of Samar in Israel is the largest of its type in the Middle East. In addition, scientists have concluded that Cerbalus aravensis is a nocturnal spider that lives in an underground den with a “lifting door” made of glued sand particles so the den remains camouflaged.

Photo by Yael Olek

Ecuador’s Scaly-Eyed Gecko
Recent exploration by U.S. and Ecuadorian researchers have found more than 30 new species of animals in Ecuador, including the scaly-eyed gecko. A full-grown scaly-eyed gecko is small enough to sit atop the eraser of a pencil. These geckos crawl along the forest floor, making them difficult to spot.

Dinosaurs’ True Colors
Two groups of researchers using electron microscope technology have determined the true colors of two species of dinosaurs.  Sinosauropteryx, a turkey-sized carnivorous dinosaur, had reddish-orange feathers and striped tail.  Anchiornis huxleyi, a chicken-sized dinosaur, had black and white wings and red crown – similar to some woodpeckers.

Sinosauropteryx, a feathered dinosaur

All-Black King Penguin
An extremely rare all-black penguin was photographed near Antartica by Andrew Evans of National Geographic.  The king penguin doesn’t look like his tuxedoed counterparts because of what one scientist described as a “one in a zillion kind of mutation.”

World’s Largest (and Toughest) Spider Web
A newly discovered spider in Madagascar builds the longest and largest orb webs in the world. The spider, called Darwin’s bark spider, builds webs over rivers that can measure up to 2.8 square meters (about 30 square feet)!  The webs are made of the toughest biomaterial yet discovered and can catch 30 or more insects at any given time.

Reclusive Loris Photographed
One of the most reclusive primates in the world, the Horton Plains slender loris, has only been spotted four times since 1937. So rare were sightings that researchers thought this loris had gone extinct sometime between sightings in 1939 and 2002.  As deforestation has led to a decline in all populations of slender loris, researchers made the effort this year to study the nocturnal primates in their native habitat in Sri Lanka and southern India.  This photo was taken as part of the study.

Giant Penguin Fossils
Scientists in Peru uncovered the fossils of a Water King, a giant 5-foot penguin that weighed twice as much as an emperor penguin (the world’s largest living penguin) and lived 36 million years ago.  The fossils, which included well-preserved feathers and scales, led scientists to determine that the Water King had brown and gray feathers, unlike the black and white feathers we associate with modern penguins, and it was a very strong swimmer and diver.

Recently scientists have announced the discovery of the true color of two dinosaurs.

One group of researchers used electron micrography to determine that Sinosauropteryx, a turkey-sized carnivore, had reddish-orange feathers and striped tail.

Another group of researchers determined that Anchiornis huxleyi, a chicken-sized dinosaur, had black and white wings and red crown – similar some woodpeckers. This group used scanning electron microscopes to study pigment samples from fossilized feathers.

To read more and see additional photos, visit National Geographic here and here.