Giant Isopod - Bathynomus giganteus

There are a few species of isopods (creatures in the same order as the woodlouse, or slater to Australians) that have been given the generic name Giant Isopod, but we'll concentrate on the biggest one here, simply because that's what we're all about.



As I mentioned above, Isopods are an order that includes arthropods related to pill bugs/woodlice/slaters, and the giant isopod is a deep-sea cousin of theirs. It lives down to a bit over 2Km below the surface, and is one of the ocean's scavengers; it lives on everything from dead fish, to whales and squid that have expired and dropped to the sea floor.



Much like some more familiar oceangoing arthropods, the Giant Isopods can be eaten, and are served much the same as lobster or crab. They're not a terribly common catch, but do come to the surface in nets of other seafood.



These guys are a rather old and stable species, appearing in fossils up to 160 million years back appearing very similar to today's creatures. One of those bodies that's found a long stable niche and been fine keeping on doing just what it does.

Patagonian Mara - Dolichotis patagonum

Another one for the multiple-creatures-rolled-into-one file*, the Patagonian Mara, which could also be named the kangaroobunnydeer. Walking like a deer, with feet a little more reminiscent of a kangaroo, and head & ears a little like a rabbit, it's another rodent. Like yesterday's porcupine, it's most closely related to guinea pigs and capybara, and more distantly related to more familiar rats, mice & hamsters.



Maras live in central & southern Argentina, and are one of the few mammals that are monogamous - Once they pair up, it's a bond for life. One pair will usually have two young each litter, three or four times a year. The fourth largest rodent, they're up to 75cm long and can weigh over 15kg.



These guys are seriously good runners, able to keep up a speed of 45km/h for more than a kilometre at a time.



* I feel I must note I'm writing from the perspective of an Australian who's more familiar with cats, dogs, horses and rabbits than the awesome variety of animals in the world. Insert your own mix of creatures if you need; if you're Argentinian, you'll just have to wait for a unique beast from elsewhere :).

African Crested Porcupine - Hystrix crystata

Here's another common one that most know by name, but mightn't have taken a close look at. Porcupines are, of course, spikey beasts that are often mixed up with hedgehogs and echidnas - unlike the others porcupines are rodents, and of the well-known rodents they're most closely related to guinea pigs and capybara.



The largest of the porcupines, Crested Porcupines can grow to almost a metre long and weigh near 30kgs. Their quills aren't the quills of the North American porcupine and its short sharp spikes interspersed with fur, but long black & white ringed spines that can grow up to half a metre long. The spines are anchored in deep muscled layers within the skin, and can be flared up or rattled depending how annoyed the little one is. Sufficiently annoyed, they make best use of their business end by launching backwards at attackers. Take a close look at the image above - that's not just a slightly spikey creature that relies on its spikes to be merely uncomfortable; its rear end is only a little less painful than diving head first into a pit of kitchen knives.

The business end, relatively laid back.

Along the top of their body down to the middle of their nose is the line of bristle that gives them their name, and it to can be voluntarily raised - just in case the massive spray of ringed needles out the other end wasn't warning enough.

The closely related Indian Crested Porcupine. Angry

The quills themselves aren't poisonous, and a porcupine can't throw them - but they're loosely enough connected that they're happy to leave a few stuck in any attacker. The spines are such an effective deterrent that a closely related Indian species has been known to fend off attacking tigers & leopards.



Not to put too fine a point on it, yes mating is performed very carefully. The quills can be voluntarily laid flat, and when receptive to a bloke porcupine, the female can lift her tail, which has no spines underneath, and lay it over the top of the spines on her back. As for giving birth, the littlest ones are born with short soft quills that only harden later.

Sue - Tyrannosaurus rex

Today's entry is a little different; instead of picking a particularly interesting species to take a look at, I'm going to concentrate on a single interesting individual of a well known common (if still interesting!) species, just because there's so much information on some of how she lived.



"Sue" is a Tyrannosaurus rex who was named after her discoverer, Sue Hendrickson. Sue the palaeontologist found Sue the Tyrannosaur almost by accident during the last days of a summer dig in 1990 in South Dakota. Sue ended up being the largest, best preserved, and most complete Tyrannosaurus rex yet found. While there's no certain evidence on the sex of Sue, some have suggested the shape of her pelvis lines up with other female reptiles who have adaptations to provide a passage for delivering eggs.

While there's an interesting story about the ownership and sale of the eventual Sue skeleton, I won't go into that here, instead I'll look at the injuries on the individual creature.

Due to the remarkable preservation of Sue, more clear info can be gathered than just her size. Lines of growth within her skeleton show she was old for a Tyrannosaur, having died after at least 28 years of life. Her bones bear the marks of a hard life that consisted of recovery after recovery from serious injury until her death, when she was quickly covered by sediment, preventing the usual scattering of bones.

Among the injuries discovered on Sue are:

A broken and healed humerus (upper arm bone)
A torn and healed tendon on one arm
Multiple broken and healed ribs on both sides (some ribs broken multiple times)
An embedded tooth fragment in one rib
Multiple skull injuries from bites and disease
Damaged tail vertebrae
Bony growths on vertebrae showing possible age-related back problems
Infections or other disease marks in jaw, arm and leg bones
Broken and healed legs on both sides

All of these except for one injury on the left of Sue's skull appear to have been breaks, bites and tears that she recovered from. It's unclear if the skull injury was caused after death or was the cause of Sue's demise, but it was just one in the lifetime of what was a very resiliant animal. Some of the injuries, such as broken fibulae, have been suggested as showing a level of social interaction beyond being isolated predators; being unable to hunt but having access to food from a mate or peer group would have helped survival after debilitating but recoverable injuries.

As for her size, Sue is larger than all previous Tyrannosaurus rex specimens. She stands 4 metres tall at the hips, and is a shade under 13 metres long. In life she would have weighed around 6.5 tonnes. The longest of her teeth was 30.5 centimetres in her 1.5m long skull.

Therizinosaurus - Therizinosaurus cheloniformis

Just for one feature, today's beast is a unique extinct one named Therizinosaurus. The first dinosaur in our exploration through the curious animals in the world, Therizinosaurus looks unlike most others for its bizarre claws, up to a metre long - indeed, it could have been labelled Freddykrugersaurus for the bizarre proportions of its hands.



First discovered in Mongolia in the late 1940s, it was the claws discovered first - they were guessed to be ribs of a turtle like creature. It wasn't until more fossils and limbs were discovered that it was clear they truly were claws, and northern chinese digs discovered substantial amounts of other Therizinosaurs, and the general body type could be determined.

Therizinosaur appears to be herbivorous, and to fill a similar niche to our first creature, the Giant Grount Sloth. Large, herbivorous, and with giant claws able to be used for grasping high and far strong vegetation. Weighing up to six tonnes and standing almost six metres tall, Therizinosaurus was a similar mass to African elephants, but far taller.

Chinese water deer - Hydropotes inermis

It's been a busy day, so just a quickie until tomorrow. This is a currently living creature that's pretty cute all up. Only weighing about 10-15kg, it's quite a small deer, but has a curious extra feature that most don't. Fangs!



Or tusks, to be correct. I understand some UK friends are quite familiar with the existence of these guys, but they're new to me - and the photo of its skull is quite striking.



The males have the larger canines-turned-tusks, where females have very tiny ones that usually aren't large enough to see from afar. The tusks are quite loosely held in their sockets, and can be moved around by attached muscles - out of the way for eating, or drawn together in order to go head to head with other males.

Dimetrodon - Dimetrodon grandis

Going back a long way here, to another extinct creature, the probably-instantly-recognisable Dimetrodon. First things first, this one isn't a dinosaur. It's ancient, sure, and it certainly looks reptilian, but it occupies a different and pretty special place for us in evolutionary history.



First, some basic detail. Let's start with some familiar numbers and a creature most of us know, Tyrannosaurus rex, who was one of the last dinosaur species alive at the very end of the Cretaceous period. Tyrannosaurus died out when the Cretaceous ended 65.5 million years ago, at the same time as a massive number of other species during the Cretaceous-Tertiary extinction event.

For some scale, look back at the entirety of recorded human civilisation, which covers the last 5,000 years (I'm rounding to nice even numbers here for the sake of scale) to the early Egyptians. Civilisation goes back a lot further of course, as do humans - forty times further back to 200,000 years ago, we have the earliest modern humans. Five times further back is just one million years. Five times further is five million years, before recognisable humans existed on the planet. Another ten times that is fifty million years, and the rise of the mammals is well underway.

A little further back, we're again at 65.5 million years, and Tyrannosaurus has just keeled over from (probably) a massive asteroid hit. It's a long way back, and even viewing the numbers above probably doesn't give us as humans a sense of the time scale involved, but numbers are all we have here.

Back to Dimetrodon. This fellow lived from 265-280 million years ago. They were walking about at least 200 million years before Tyrannosaurus, who is almost a neighbour of ours in comparison. It lived so far back it pre-dates all of the dinosaurs.

If Dimetrodon isn't a dinosaur, where does it fit? Its sideways splayed legs were like primitive reptiles, unlike dinosaurs with their legs underneath. While it was reptilian-like, it had already split from the true reptile side of the family and developed some interesting features that would eventually takes its family (the Synapsids) down the path to becoming mammals. It likely no longer had scales to the level of reptiles but naked skin instead, and its teeth had differentiated into multiple specialised types - that's where it gets its name, Dimetrodon literally means two measures of teeth. This same specialisation of tooth types lead to the range of teeth we have in our own mouths.

The massive sail on its back seems to have been an aid in controlling body temperature. When faced into the sun it may have reduced the time to wake up to an operating temperature by almost two thirds. It may have been able to wake up and move around energetically hours before its prey were able to warm up and escape.



As far as size, Dimetrodon reached up to 3.5 metres in length, and looks to have been the largest predator of its time. We can perhaps be thankful that even though Dimetrodon died out at the end of the Permian period before the rise of the dinosaurs, its kind (the Synapsids) survived; we too are Synapsids.