The Jesus Christ lizard that walks on water!

By on March 16th 2010 in Animals

Amidst the tropical streams and rivers of Central and South American rain forests live some of the most extraordinary creatures of our planet: the Jesus Christ lizard. Next to lizards that look like miniature dragons and that don’t need sex, these lizards more properly known as basillisks may be even more spectacular: they have the seemingly miraculous ability to run across water!

Jesus Christ lizard walking on water

The Jesus Christ lizard is able to run on water to escape predators!

Slapping their long-toed feet hard against the water they create a tiny air pocket that keeps them from sinking. This in combination with loose skin between their toes, enables them to move along the surface for over 5 meters. Luckily when gravity eventually takes over, these amazing lizards can rely on their excellent swimming skills.

Their ability to run on water is primarily an escape mechanism, giving them precious seconds when being threatened. Since lizards are cold-blooded (their internal temperature varies along with that of their environment), they need to bask in the sun to warm up each day, leaving them very vulnerable to being caught by predators.

Recently released high-definition footage from the BBC shows in slow-motion how these amazing lizards run across the water

Not everybody likes the special nickname of these amazing lizards, which refers to a specific passage in the bible. Look at the following senseless quote, which shows how some people still think about our fascinating natural world:

It’s blasphemous to name a reptile of all creatures after our Lord Jesus Christ when lizards are symbols of devils.

No sex needed in all-female lizard species

By on February 22nd 2010 in science

Already half a decade ago scientists found that some species of lizard do not need males to reproduce. However it has remained unclear how they can do this since asexual reproduction goes together with almost no genetic variation and higher disease vulnerability. A new study published online in Nature on the 21st of February reveals how.

Asexual all-female lizard

The asexual, all-female species (center) is shown flanked by two sexual species which hybridize to form the middle species. Photo by Alistair J. Cullum.

The all-lady lizard species are not alone in the vertebrate world of asexual reproducing species – some 70 species multiply in this way. However, these little lizards do not have a choice. Sexual reproduction has the advantages of rapid generation of genetic diversity, allowing adaptation to changing environments. Since these lizards can’t exchange genetic material, they have a major disadvantage in a changing environment.

Asexual lizard pseudocopulation

Two Desert Grassland Whiptail lizards engaged in pseudocopulation. Photo by Tino Mauricio.

The new research by Peter Baumann and his team reveals that these lizards maintain genetic richness by starting the reproductive process with twice the number of chromosomes than sexual lizard species. The researchers found that these species could maintain diversity and form a gamete by pairing their sister chromosomes (the two chromatids from one chromosome), while in sexual species homologous chromosomes from each parent are paired.

These celibate species have arisen through the hybridization of two or even three different sexual species. Although the precise mechanism is not known, it gives the individual asexual species a great amount of genetic diversity to begin with.

Asexual whiptail lizardsAn interesting aspect to reproduction in these asexual lizards is that mating behavior still occurs even though the populations are all female. One female plays the role of a male and mounts the female that is about to lay eggs. This behaviour is due to hormonal cycles. Since lizards who act out the courtship ritual produce mroe offspring, it can be said that they still require sexual behaviour for maximum reproductive success.

Though asexual reproduction sounds not really exciting, it has great benefits. Reproducing without the need of a male greatly increases the chances of populating a new environment. Living in the dry and sometimes harsh climate of the southwestern United States and northern Mexico, this unique way of reproducing may be the most optimal.

A further understanding of the small but diverse group of animals that reproduce without males is needed, and may shed light on the overwhelming success of sexuality.

Lutes, A. A., Neaves, W. B., Baumann, D. P., Wiegraebe, W., Baumann, P. (2010) Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards. Nature 2010/02/21/online

The dragon-like Gliding lizard

By on February 16th 2010 in Animals
Gliding lizard with wings

The amazing-looking gliding lizard looks like a miniature dragon!

This amazing looking creature may appear to be a miniature dragon, but is actually a gliding lizard. These lizards use their wings to fly from tree to tree which enables them to quickly get away from predators. Oddly enough, the wings are just a very well rearranged rib cage. By elongating their extended movable ribs, spanning the large flap of skin between their limbs, these arboreal reptiles can glide distances of over 60 meters.

Gliding lizard wings

A Gliding lizard on a tree

Interestingly, these living hangliders have a small set of flaps on their neck that serve as a horizontal stabilizer and a rudder-like tail to steer. Different species of gliding lizards may occur together because of differences in flight anatomy which separates them ecologically. Light species with big wings have a lot of maneuverability and live closer to the ground, while in contrast heavy and more robust species live mostly high up the tallest trees since they need a lot of speed for their wings to open up.

Although these fascinating lizards have great areal skills, most of the day they run up and down trees feeding on ants. Furthermore, their wings are also used to attract a mate. By showing off their vibrantly colored wings, the territorial males try gain attention of a female.