Good afternoon readers. Today we are bringing you a specimen that is feared by humans and can grow up to eight feet long. This animal is known for the distinctive sound it makes to when trying to deter predators or intimidate prey. It is long, scaly and has a bit of bite, this week’s Specimen of the Week is… (more…)
Slow worms – They don’t have a leg to stand on
Not all legless reptiles are snakes, like this slow worm which is just one of the many kinds of legless lizards. The complete or near loss of limbs has evolved in lizards a great number of times. Some entire lizard families are legless. Some families contain a few species with tiny vestigial limbs, while the rest are limbless. Some families are mostly “normal” four-limbed species, with limblessness, near limblessness, or two-leggedness having evolved in certain lineages independently. The biggest lizard family – the skinks (of which there are 1500 of mostly leggy species) – has groups that have lost their limbs on numerous occassions in Africa, Europe and Australia. In most cases of legless lizards, some remnant of the hindlimbs is visible, often by the precence of scaly flaps.
Leglessness evolves when the legs become a hindrance rather than a help in an animals’ locomotion, and in lizards this is normally to do with burrowing. Essentially lizards have found that it is more effective to “swim” through the soil, pushing their way through little gaps with their heads. If you think about it, this makes sense because lizards’ arms aren’t that close to their snouts, so using them to dig can be a it awkward. This is one also one of the main hypotheses for how and why snakes evolved. Swimming is also a driving factor for losing limbs.
How do you tell a snake from a legless lizard?*
When the language of biology meets common parlance there’s often a lot of confusion. Biological nomenclature (often called the scientific name, we are Homo sapiens sapiens* for example) is by and large controlled using strict rules, format and notations but there aren’t quite so strict rules when it comes to the common names of animals or groups of animals. Some animals we refer to by their taxonomic name, for example; Tyrannosaurus rex, Hippopotamus, Octopus** and Bison. For other animals however, their common, useful to most people and widely understood names create all kinds of problems for the pedantic as I’ve written about before when is comes to sea stars vs starfish. My colleague Jack Ashby wrote about when it comes to seals and sea lions. Consider also that a musk ox is a goat-antelope, horseshoe crabs aren’t crabs at all and the Grant Museum favourite: flying lemurs aren’t and don’t.
The idea of ‘true’ and ‘false’ animals can also be misleading and a lot of pub discussions/arguments/bets come from animals which aren’t what they are often called or even named. How do some animals end up as the ‘true’ and ‘false’ versions of their group. Let’s have a look at some ‘true’ animals and see how the philosophical concepts of truth has ended up in our zoological lexicons.
Once upon a time there was a rattlesnake, he lived in the high desert of North Western New Mexico. No doubt conceived in love, he was born live, not out of an egg like most other snakes. He grew up big and strong, lithe and supple, with dark diamond-shaped patterns along his back. When he was growing up, he grew larger than his skin so he slipped out if it, shedding the thin scaly coat on the sandy ground and not looking back.
A delayed account of zoological fieldwork in Australia – Part 14
From April 2010 I spent about five months undertaking several zoological field projects across Australia. I worked with government agencies, universities and NGOs on conservation and ecology studies ranging from Tasmanian devil facial tumour disease, the effect of fire, rain and introduced predators on desert ecology and how to poison cats. This series of blog posts is a delayed account of my time in the field.
Weeks Sixteen to Nineteen – part 3
In the last couple of weeks I’ve been describing the final field project on this trip, joining ecologists from the Australian Wildilfe Conservancy (AWC) on a full faunal survey of their sanctuary on the Arhnem Land Plateau in the Northern Territory. During this one month expedition I encountered more snakes than I had throughout my whole life previously. Snakes on field work is the topic of this week’s post.