Though it’s only 2.8-4.3 inches wide, the terrestrial crab Johngarthia lagostoma is the largest native land animal on Ascension Island, one of four islands in the South Atlantic where it’s found. Since these crustaceans cannot swim, the method by which they arrived on an isolated island like Ascension remains unknown–though some speculate that smaller islands, now underwater, could have helped these crabs arrive at their current homes. Species introduced by Europeans in the 19th century, include mice, rats, and rabbits, now compete with these endemic land crabs.

On Ascension–a volcanic island–most of the crabs are yellow-orange, but some are dark purple, which may help them hide from predators. Their larvae are marine, and adults migrate to the water in the rainy season to release their offspring, with mating taking place along the way. During this time, as the crabs travel from their range in the mountains to the sea, they can cover roughly 1,480 ft per day.

While not normally arboreal as adults this large male Blue Iguana climbed this tree after significant rainfall which left the ground slightly flooded.

In 2007 I had the great privilege of visiting Grand Cayman Island to work with and document the critically endangered Grand Cayman Blue Iguana (Cyclura lewisi) with the team at the Blue Iguana Recovery Program founded by Fred Burton.

Blue Iguanas are endemic only to the small island of Grand Cayman and as such are at risk habitat destruction, road kills, free-roaming dogs, and feral cats. Thankfully the Blue Iguana Recovery Program (B.I.R.P.) has brought this beautiful iguana back from the brink of extinction with breeding and release programs as well as the acquisition of habitat.

It is the largest native land animal on Grand Cayman with a total nose-to-tail length of 5 ft (1.5 m) and weighing as much as 30 lb (14 kg).

Nikon D200 + Sigma 70-200mm
f5.6 1/400sec ISO640

#iguana #blueiguana #caymanisland #grandcayman #caribbean #wildlife #wildlifephotography #WildlifeConservation #shannonwild #reptile #lizard #blue


Why Tyrannosaurus was a slow runner

…and why the largest are not always the fastest

No other animal on land is larger than an elephant - but the fastest runner is the medium-sized cheetah.

A research team under the direction of the German Centre for Integrative Biodiversity Research (iDiv) and the Friedrich Schiller University Jena have now described why the largest animals are not the fastest.

They have managed to so thanks to an amazingly simple mathematical model. The only information that the model must ‘be fed’ with is the weight of a particular animal as well as the medium it moves in, so either land, air or water. On this basis alone, it calculates the maximum speed that an animal can reach with almost 90% accuracy.

“The best feature of our model is that it is universally applicable,” says the lead author of the study, Myriam Hirt of the iDiv research centre and the University of Jena. “It can be performed for all body sizes of animals, from mites to blue whales, with all means of locomotion, from running and swimming to flying, and can be applied in all habitats.” Moreover, the model is by no means limited to animal species that currently exist, but can be applied equally well to extinct species.

“To test whether we can use our model to calculate the maximum speed of animals that are already extinct, we have applied it to dinosaur species, whose speed has up to now been simulated using highly complex biomechanical processes,” explains Hirt.

The result is that the simple model delivered results for Triceratops, Tyrannosaurus, Brachiosaurus and others that matched those from complex simulations - and were not exactly record-breaking for Tyrannosaurus, who reached a speed of only 27 km/h (17 mi/h).

“This means that in future, our model will enable us to estimate, in a very simple way, how fast other extinct animals were able to run,” says the scientist.

Two assumptions are the basis of the model. The first assumption is related on the fact that animals reach their maximum speeds during comparatively short sprints, and not while running over long distances. Unlike running over longer distances, where the body constantly resupplies the muscles with energy (aerobic metabolism), sprinting uses energy that is stored in the muscles themselves but which is exhausted relatively quickly (anaerobic metabolism).

It seems logical enough: the larger the animal, the more muscle it has - and thus the faster it can sprint. However, Newton’s laws of motion also apply in the animal kingdom, we know mass has to overcome inertia, and so a five-tonne African elephant simply cannot start moving as quickly as a 2.5-gramme Etruscan shrew.

By the time large animals such as the elephant get up to full speed while sprinting, their rapidly available energy reserves also soon run out. Taken together, these two assumptions result in the previously mentioned curve: A beetle is slower than a mouse, which is slower than a rabbit, which is slower than a cheetah - which is faster than an elephant.

TOP IMAGE….Tyrannosaurus Rex meaning “tyrant lizard king”, is a genus of coelurosaurian theropod dinosaur.

UPPER IMAGE….The African elephant is the largest animal on land, but not the fastest. Credit Bernd Adam

CENTRE IMAGE….There is a parabola-like relationship between the body mass of animals and the maximum speed they are able to reach. For the first time, researchers are able to describe how this comes about, thanks to a simple mathematical model. Credit Myriam Hirt

LOWER IMAGE….The new model also provides results for extinct species which agree with the results produced by highly complex biomechanical simulations. Credit Myriam Hirt

BOTTOM IMAGE….Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, Tyrannosaurus fore limbs were short but unusually powerful for their size and had two clawed digits. The most complete specimen measures up to 12.3 m (40 ft) in length, up to 3.66 meters (12 ft) tall at the hips, and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight.


Press play, then drag the screen around for a 360 degree experience meeting the Titanosaur, the largest dinosaur (and largest land animal) ever discovered.


Agathaumas (“great wonder”) is a dubious genus of a large ceratopsid dinosaur that lived in Wyoming during the Late Cretaceous (late Maastrichtian stage, 66 million years ago). The name comes from Greek, αγαν - ‘much’ and θαυμα - 'wonder’. It is estimated to have been 30 ft long and weighed 6 tons, and was the largest land animal known at the time of its discovery.

It was the first ceratopsian known to science, though relatively little is known about it. The original specimen consisted only of the animal’s hip bones, hip vertebrae and ribs, and because these bones vary little between ceratopsid species, it is usually considered a nomen dubium. It is provisionally considered a synonym of Triceratops, but is difficult to compare to that genus because it is only known from post-cranial remains.

wow first there was the discovery of the dreadnoughtus, the largest land animal ever (and still growing when it died), and now there’s the spinosaurus, a swimming dinosaur. it’s been a great week in dinosaur discoveries and idk why no one else is excited about it