animals
edyong | July 14, 2008Evolution dances to the tune of death. Killers - be they predators, diseases or competitive peers - can radically shape a species' life cycles by striking down individuals of a certain age. The survivors respond by changing their "life histories" - a collection of traits that defines their reproductive cycles, including how often they breed, when they start to do so and how many young they have.
If an animal's adult life is short and brutal, they tend to grow quickly and become sexually mature at a young age - a strategy that maximises their chances of siring the next generation. The…
edyong | July 12, 2008
There is an old joke that if Spider-Man has the powers of a spider, he really ought to be shooting webs from somewhere less salubrious than his hands. In the films and comic books, Peter Parker is empowered with the powers of a human-sized arachnid through a spider bite. He effortlessly scales walls and ceilings and shoots sticky webs from his wrists. Now, scientists have found a type of spider that does just that.
Like Spider-Man, most spiders can climb sheer surfaces and they do so with two techniques. The most obvious are small claws, called tarsi, that grip onto rough surfaces.…
edyong | July 7, 2008New parents are often extremely picky about where they live, seeking the right combination of spacious housing, local schools, and safe neighbourhoods for their tiny sprogs. A mother mosquito is no less choosy but unlike the white-picket-fence ideal of middle-class humans, she prefers areas of stagnant water, including artificial ones like rain-filled buckets or clogged drains.
But she's not looking for just any old bucket of sluggish water. A new study reveals that a pregnant Aedes aegypti mosquito seeks out just the right patch by tasting for chemicals given off by bacteria in the water.…
edyong | July 3, 2008Spider silk is a most amazing and versatile material, and spiders put it to all sorts of uses. It helps them to climb, to travel from place to place and most famously, to ensnare their prey. But one group of spiders, the uloborids, use their silk in a unique way - as a murderous garbage-compactor.
Most spiders kill with venom and even those that pose no threat to humans pack enough poison to deal with insect prey. Their famous webs are simply elegant traps, designed to immobilise prey so that the spider can deliver a fatal bite. But the uloborid spiders have uniquely lost their venom…
edyong | July 1, 2008The mayfly is known for its incredibly short adult life. After spending months as larvae, the adults finally hatches only to fly, mate and die within the space of a day. Now, in the dry south-west corner of Madagascar, scientists have discovered the lizard equivalent of the mayfly - Labord's chameleon (Furcifer Labordi).
The lifespan of Labord's chameleon is hardly as compressed as that of a mayfly, but it is extraordinarily short for a tetrapod (an animal with four legs and a backbone). From laying of egg to kicking of bucket, the lizard's entire life is played out in a year and 7 months…
edyong | June 27, 2008For humans, sight is the most important of senses but only after we are born. Within the womb, surrounded by fluid, muscle and darkness, vision is of limited use and our eyes remain closed. But not all animals are similarly kept in the dark.
Cuttlefish develop inside eggs that are initially stained black with ink, but as the embryo grows and the egg swells, the outer layer slowly becomes transparent. By this time, the developing cuttlefish's eyes are fully formed and we now know that even before they are born, they can use visual information from the outside world to shape their adult…
edyong | June 26, 2008I've written two news stories in this week's New Scientist. One is on the different tactics of four-year-old boys and girls as they compete for animal puppets. The other is on the webs spun by black widow spiders. The article on the venomous, evil, little critters is longer so I'm going to use this space to talk about the black widows instead...
Black widows are notorious for both the toxicity of their venom and the cannibalistic nature of their sex, but their webs are equally interesting and less well known.
The basic design - the "sheet-based" web - consists of a well-defined horizontal…
edyong | June 25, 2008If you listen to the egg of a crocodile, you can tell when it's going to hatch by the small squeaks coming out of it. The squeaks come from the unborn babies and sound like "umph! umph! umph!". These calls are common to all crocodilians and while zoologists have always suspected that they serve a specific purpose, until now, no one had ever tested this theory with an experiment.
Amelie Vergne and Nicoals Mathevon at the Universite Jean Monnet are the first to do so and they show that the youngsters call to tell their siblings that it's time to hatch. And given that Nile crocodiles bury…
edyong | June 24, 2008In 1994, a third of the lions in the Serengeti were killed off by a massive epidemic of canine distemper virus (CDV), an often fatal infection that affects a wide range of carnivorous mammals. Seven years later, a similar epidemic slashed the lion population in the nearby Ngorongoro Crater. While CDV was undoubtedly involved, the scale of the deaths was unprecedented. What was it about the 1994 and 2001 epidemics that claimed so many lives?
Now, a team of scientific detectives led by Linda Munson from the University of California Davis, have solved the mystery. It turns out that the lions'…
edyong | June 23, 2008In 2004, the Australian Government turned a third of the Great Barrier Reef into the largest network of no-fishing zones in the world. All fishing was banned in an area of sea just smaller than England. It was a bold and controversial political move - jobs and livelihoods, it was said, were on the line. But the plan went ahead and in just a few years, there are signs that it's working. One of the reef's most heavily fished species - the coral trout- is enjoying a dramatic comeback, thanks to this most ambitious of marine conservation projects.
The vast expanse of the Great Barrier Reef is…
edyong | June 18, 2008In my last post, I wrote about how chimpanzees console one another to reduce the stress of violent confrontations. Conflict and competition are clearly important parts of chimp life and never more so than when sex is involved. The second study this week on the social lives of chimps demonstrates one of the strategies that female chimps use to avoid competition in some cases, and stir it up in others.
It comes down to sex calls - distinctive calls that female chimps make while mating. New research shows that they do this to advertise their availability to other males and garner both sperm and…
edyong | June 17, 2008Humans are intelligent and social animals. We are devious in fending off competition, we use guile and strategy to attract partners, and we extend acts of kindness towards friends in need. Many people suffer through the inanity of reality TV for the odd glimpse of these social interactions. But humans aren't the only animals with complex social lives - those of chimps are just as fascinating and news of their exploits can be found in scientific journals.
Just this week, two new papers shed new light on the rich social lives of chimps. They are filled with just as much drama and deception…
edyong | June 16, 2008Jellyfish may seem like simple blobs of goo, but some are surprisingly sophisticated. The box jellyfish (Tripedelia cystophora), for example, is a fast and active hunter and stalks its prey with the aid of 24 fully functioning eyes. These are grouped into four clusters called rhopalia, which lie on each side of its cube-like body. Together, they give the box jellyfish a complete 360 degree view of its world and make it highly manoeuvrable.
Each eye cluster, four eyes are merely pits containing light-sensitive pigments, but two are remarkably advanced and carry their own lenses, retinas and…
edyong | June 13, 2008Many groups of animals, from humans to dinosaurs to kangaroos, have evolved the ability to stand and walk on two legs. In all of these cases, the move from four legs to two has provided clear advantages. Kangaroos save energy because their hopping is so efficient, birds have freed their front pair of limbs for use as wings, and humans use ours for manipulating tools and objects.
But some species of lizards also rear up on their hind legs from time to time, particularly when running. The Australian frilled lizard does it so readily that it has earned the nickname of 'bicycle lizard'. And the…
edyong | June 5, 2008
On Wednesday, I posted about a parasitic wasp that turns a caterpillar into both a living incubator and a zombie-like bodyguard for its larvae. Well, it seems to be a bumper week for wasp research; today, we have yet another demonstration of the amazing tactics used by these macabre parents to provision their young with food.
The stunning colours of the jewel wasp (Ampulex compressa) belie its gruesome habits. Its grubs feed on the bodies of cockroaches supplied by their mother. When a female wasp finds a roach, she stings it twice - once in its mid-section to immobilise its front…
edyong | June 3, 2008Bodyguards have a tough and risky job but they usually get paid for their trouble. But not the caterpillar of the geometer moth. Against its will, it is recruited to defend the developing young of a parasitic wasp, and the only 'reward' it gets for its trouble is to be eaten inside out by the larvae of its attacker.
The vast majority of wasps are "parasitoids", animals that practice the grisly art of body-snatching. They lay their eggs in the bodies of other living animals to provide their newly hatched grubs with a fresh supply of meat. Like HR Giger's alien, the full-grown larvae then…
voltagegate | June 2, 2008
I finally got around to blogging about this study published in PLoS One a few weeks ago, regarding geophagy in tropical species of bats. The study provides a nice overview of the literature and some of the potential reasons why they (and we) do it.
We all eat dirt, in a sense, through mineral supplements or through the minerals and inorganic nutrients contained in our food, but there is a long history of the consumption of clay by human beings, and some tribes in sub-Saharan Africa continue to visit these "clay licks". Pregnant women in particular will frequent these licks. Scientists…
edyong | June 1, 2008
You inherited your genes from your parents, half from your father and half from your mother. Almost all other animals contend with the same hand-me-down processes, but not the bdelloid rotifers. This intriguing group of small freshwater creatures are not content with their genetic hand-me-downs; they import genes too. A new study shows that their genomes are rife with legions of foreign DNA, transferred from bacteria, fungi and even plants.
The swapping of genetic material is all part of a day's activity for bacteria but it's incredibly rare in animals. But bdelloids are bringing in…
grrlscientist | May 30, 2008tags: mountain cow, Baird's tapir, Tapirus bairdii, mammals, streaming video
This streaming video shows you a little bit about the mountain cow .. the tapir. In this case, the Baird's Tapir, Tapirus bairdii, the state animal of Belize, a country in Central America. This animal, which is endangered, is not a cow at all, but is related to horses and rhinoceros [1:47].
There is one mistake on this video. When a person discovers a new species they cannot name it after themselves -- that's a rule.
grrlscientist | May 26, 2008tags: turtles, turtle yoga, reptiles, Central Park, Image of the Day
Turtle Yoga Chaos!
Image: Bob Levy, author of Club George [larger].
The photographer, Bob Levy, writes;
This image captures a group of unfortunate Central Park turtles sorely in need of a yoga master. The chaos, as the Great Oz once said is," The result of disorganized thinking." Finding such a chaotic demonstration of yoga art shocked this observer who has grown used to watching turtles execute poses with precision and grace. Will a yoga master arise to lead the others and bring order to the class and the universe or at…