Tabla de contenidos para January 2023 en Practical Reptile Keeping

A specimen retrieved from a cupboard of the Natural History Museum in London has shown that modern lizards originated in the Late Triassic and not the Middle Jurassic as previously thought. This fossilised relative of living lizards such as modern-day monitor lizards, gila monsters and slow worms was identified in a stored museum collection from the 1950s, featuring specimens found in a quarry near Tortworth in Gloucestershire, in the south-west of England. The technology didn't exist then to expose its contemporary features, and so its significance was not realised at that stage. Modern technology confirms the fossil's identity As a modern-type lizard, the new fossil impacts all estimates of the origin of lizards and snakes, together called the Squamata, and affects assumptions about their rates of evolution, and even the…

The Field Museum in Chicago is home to the best, most-complete fossils of a prehistoric superpredator-- but one that lived hundreds of millions of years before Tyrannosaurus rex. Whatcheeria was a lake-dwelling creature measuring 1.8m (6ft) in length, with a salamander-like body and a long, narrow head; its fossils were discovered in a limestone quarry near the town of What Cheer, Iowa. There are around 350 known whatcheeria specimens, ranging from single bones to complete skeletons that have been unearthed, and all of them reside in the Field Museum’s collections. Research involving these remains has helped to reveal how whatcheeria grew big enough to menace its fishy prey: instead of growing in a slow and steady manner, in common with most modern reptiles and amphibians, it grew rapidly in its…

FEATURE | SURVIVAL LESSONS It is now clear that frogs are very capable of learning, in various situations and in lots of different ways. But when you want to investigate the abilities of a group of animals that has not been tested much previously, it is most important as a starting point to find appropriate tests that can truly and fairly reflect their abilities. Ask the right questions The use of inappropriate tests often leads to the assumption that a group of animals is stupid or unable to learn. Firstly, it is vital to give them a motivation to perform. In the case of frogs, this usually involves one of two issues – either receiving food or avoiding predators. Next, the tests themselves need to be matched to the species.…

FEATURE | GREEN IS THE COLOUR Just like most people, green snakes have always been something I have admired with great passion. There just seems to be something about this colour that makes them so appealing and attractive to watch. Perhaps it is tied in with our perceptions of our world – green grass, trees and even vegetables – we almost instinctively see it as natural and therefore appealing? Green is also a colour that we associate closely with the environment, the ecosystem and regeneration. Unfortunately though, as far as snakes are concerned, the vast majority of green snakes are difficult to obtain, and can be hard to keep, highly priced or venomous! Green tree pythons and emerald tree boas are amongst the most commonly available, but they require experience,…

REGULAR | HERPETOLOGICAL MYSTERIES Herpetological Mysteries Has North America's most deadly snake yet been found? Some time ago, I investigated a mysterious, highly-venomous mini-snake named Karait – a memorable albeit short-lived character briefly included by Rudyard Kipling in his story 'Rikki-Tikki-Tavi', which featured in the first of his two Jungle Book novels. Kipling never specified Karait's taxonomic identity, with the snake being killed by the mongoose whose name features as the subject of the story. However, as I revealed on these pages in a detailed investigation some time ago, this dust-dwelling yet deadly snakeling may well have been based upon the Indian saw-scaled viper (Echis carinatus). And yet now, there is another unusual twist to this story. For it is nothing if not intriguing that a cryptozoological (or scientifically unrecognised) snake…

Urbanisation has dramatically transformed landscapes around the world—changing how animals interact with nature, creating "heat islands" with higher temperatures, and adversely affecting local biodiversity. Yet many organisms survive and even thrive in these urban environments, taking advantage of new types of habitat created by humans. Researchers studying evolutionary changes in urban species have found that some populations, for example, undergo metabolic changes from new diets or develop an increased tolerance of heat. Physical changes Clear signs have now been detected in a study of the Puerto Rican crested anole (Anolis cristatellus)—a species found in both forested and urban areas on this Caribbean island—that highlight how some are adapting successfully to city living. The genetic variations linked to urbanisation underlie physical differences in this particular group, and include longer limbs and…

It can jig along at over 80kph (50mph), and leap as far as 9m (30ft) or so in a single bound, but this speed and athleticism counts for nothing at a sub-Saharan river bank, where the impala is forced to pause and drink in the 37°C (100°F) heat. Hidden out of sight in the muddy river, a Nile crocodile (Crocodylus niloticus) has been waiting patiently for over an hour, in the hope of gaining a meal. When the unseen apex predator breaks the water surface at speed, its infamous teeth latch on to the small antelope's hindquarters with 2270kg (5000lb) of force, dragging it under to its death. Yet in spite of its overwhelming power, it is actually the water in the river that does the killing, with the slowbreathing…

Mummified animals, including crocodiles, are common finds at Egyptian archaeological sites. But despite several hundred mummified crocodiles being available in museum collections worldwide, they are not often examined thoroughly. It is clear, however, that crocodiles were significant in ancient Egyptian culture, with a crocodile deity called Sobek being recognised, so-called ‘sacred ‘ crocodiles being kept and mummified crocodiles having been prepared. More than one species In this case, the authors analysed the morphology (outline) and preservation of ten crocodile mummies found in rock tombs at the site of Qubbat al-Hawā on the west bank of the Nile. The mummies included five isolated skulls and five partial skeletons, which the researchers were able to examine without unwrapping or using CT-scanning and radiography. They were in varying states of preservation and completeness.…

OUT OF AFRICA | NAMIBIA There is no escaping the fact that Namibia is a huge country. Covering some 825,000 square kilometres (320,000 square miles), it nevertheless has a similar population to that of Botswana, consisting of about 2.5 million people. Travelling through the country, you could be forgiven for thinking that you were on a different planet with its rugged mountain ranges, and vast open expanses of sand. There are in fact four deserts which make up Namibia (the Kalahari Desert, Nama Karoo, Namaqualand, and the Namib Desert), each of which have their own bio-type and unique flora and fauna. A high count Perhaps unsurprisingly, given its size and geographical variety, Namibia is home to a large number of reptiles. There are 250 species known to occur within the…

New research has identified how social spiders evolved different ways of hunting in groups. Spiders are normally solitary creatures but a few species have evolved to be social and live in groups, known as colonies. The importance of the environment While these spiders have evolved socially similar behaviours—living in large family groups that share both communal nests and spiderling care duties—the findings suggest environmental conditions may have shaped how species developed different strategies of cooperating when hunting. An international team of researchers, led by the University of Portsmouth in the south of England, have explored the different responses to prey stuck in the webs among three social species of velvet spiders and found substantial differences between them. They found that each species attacked prey differently to what would be expected…

FEATURE | GROW YOUR INTEREST When someone starts out in search of a pet lizard, they will generally seek advice on the internet, from books and pet store staff. Both leopard geckos and bearded dragons are now firmly established in most people's minds as the two ideal "beginner's species", and few people look beyond these to other possible types of lizard when they are starting out. At the outset Acquiring a new lizard is always exciting, and can get the heart pounding! Trust me - feel like this even after nearly 20 years in the hobby, but certainly, your first reptile is one that you will never forget, and hopefully, especially if all goes well, it will be the start of a long-term interest in this field. Quite often though,…

It can be quite a commitment taking on a pet turtle, as they can easily live up to 30 years, and sometimes even longer. Their lifespan is generally at least double that of the vast majority of snakes and lizards, and although turtles are not as demanding as mammalian pets, they will require feeding several times a week throughout this period, and their quarters will need regular cleaning. The good news, though, is that it is now much easier than ever before to keep turtles satisfactorily in the home. This is partly thanks to advances in heating and lighting technology, but perhaps overall, it is the development of specially formulated diets for them that have transformed their care. In the past, keepers were forced to rely on foods such as…

Also known as both the Indochinese and Vietnamese box turtle, this Asiatic chelonian is now considered to be critically endangered. This is mainly because it has been very heavily hunted over recent years throughout its range, where it is confined to areas of woodland at relatively high altitudes. Although these turtles are adept at hiding in the undergrowth, hunters use trained dogs to track them down. While nominally protected through its range, which covers parts of China, Vietnam and Laos, effective protection is very hard to enforce. Habitat clearance is exacerbating their steep decline in numbers as well. What makes the conservation of these turtles even more difficult, however, is the problem of determining their taxonomy accurately. Flowerback box turtles have a very diverse appearance, and certain populations currently represented…

FEATURE | ARID PLANTED SET-UP The surge of interest in planted habitats over recent years has led to an expanding interest in this area - extending to the practicalities of creating arid-style enclosures. It certainly possible to create and maintain a habitat of this type, but unfortunately, this can often be tricky, in comparison with a tropical set-up. However, over the past six months, I have been testing a range of arid bioactive substrates, as well as investigating various planting ideas. In common with all planted set-ups, the fundamental concern must be to design a habitat that is suitable for its future occupants.This will dictate how and what you can do with the tank, from the outset. Unfortunately, I hear so many people who want to create a planted environment…