Posted on 26 October 2012.
The “grandmother hypothesis” has received mathematical support from a recent study involving computer simulation. This renowned theory postulates that human developed longer lifespan as adults than apes due to grandmothers helping in the feeding of their grandchildren. The theory was first advanced in 1997 by university of Utah anthropologists Kristen Hawkes and James O’Connell, together with Nicholas Blurton Jones, an anthropologist at UCLA.
Kristen Hawkes, a prominent anthropology professor at Utah University conducted this recent study together with Peter Kim, a mathematical biologist and former postdoctoral researcher at the same university currently based in university of Sydney and James Coxworth, an anthropology doctoral student at the University of Utah. The study was financed by the Australia’s Research Council and National Science Foundation.
The computer simulation shows that animals with lifespan similar to Chimpanzees evolve to acquire human lifespan in less than 60,000 years with a little “grandmothering”. While human females live for a number of decades after child bearing, female chimpanzees hardly ever live past their child-bearing years, which are normally their 30’s and at times their 40’s. This simulation did not consider assumptions about the human brain size. Continue Reading
Posted in Animals, Research
Posted on 20 August 2012.
The elephants’ sound is much like singing, not purring, when they rumble at friends and foes. This sound is heard for many kilometers away. Though humans can’t hear it, their infrasonic elements are very much alike to a cat’s purring. Scientists measured the sound of a dead elephant and they figured out that it might be bigger, similar to someone singing or speaking.
Cats are purring when their muscles contract very quickly. There were speculations that some of the elephant’s muscles, when contracted, give birth to a a very low infrasound. One scientist from the University of Vienna, Christian Herbst, said that an elephant could make these kind of rumbles, just exhaling air. His conclusion is that the purring premise is not quite true. He tries to study the lowest song of the elephants on the 3rd of August for the interest of science. Continue Reading
Posted in Animals
Posted on 30 January 2012.
Jumping spiders falls under the category of invertebrates. For many years scientist was really amazed as how spiders manage a sophisticated nervous system with their hunting behavior. A detailed research was done on Adanson
jumping spiders who fall in the category of eight eyed spiders. Four eyes are present of the face of the spider and have the sharpest vision. The jumping spiders have four distinct layers of light sensitive at the back of the eyes but the uses of these four light sensitive tissues had not been found so far. It is found that if any object falls on the base layer that object cannot be seen on the next layer up and the object becomes blurrier. Continue Reading
Posted in Animals
Posted on 25 July 2011.
It may be one of the strangest things you’ve ever seen: a dolphin swimming through the waters of the ocean with a sponge fitted over its beak. What in the world? The intelligent marine dwellers have found a way to protect their faces as they scour the rocks and broken coral for food stuffs. Rather than tearing the skin on the beaks and faces, they have devised this ingenious tool to be able to safely forage.
Researchers had thought, at first, that it would simply make more sense for the dolphins to feed from the mid-waters rather than along the bottom of the sea. In fact, the fish and crustaceans that inhabit the bottom of the ocean are more nutritious for the Shark Bay dolphins. The dolphins must have known this all along; developing a method of hunting safely instead of turning to other food sources that provide a less sound diet.
After studying the behavior of these dolphins, researchers found that hunting with sponges is an activity primarily carried out by the female of the species. It is thought that this is because of the pressures faced by a mother who has to rear her young for almost 5 years at a time. As the young swim and forage with their mother, they learn the interesting sponging technique which they, then, pass onto their young.
Sponge fishing works as such: a Shark Bay dolphin will fit a sponge onto its beak and scrape it along the bottom of the ocean. A fish will scare up from the bottom, the dolphin drops its sponge, heads to the surface for a breath of air and then dives down for its meal. The emerging fish will swim for several meters before it attempts to rebury itself, giving the dolphin the time it needs to drop, breathe and dive. A study conducted by Eric Patterson, a graduate student at Georgetown University, showed that by sponging, a dolphin can scare up a prey fish about every 9 minutes, making hunting in this manner extremely rewarding.
Posted in Animals
Posted on 02 November 2010.
Next time you’re taking a walk through the bush, stop and listen. It might sound peaceful, but don’t let that fool you. There’s a war going on in those trees. And it’s not pretty.
In a battle for resources, the species getting the most with the least effort will usually succeed while its competitors will struggle to keep up.
At first glance, the drywood termite Cryptotermes secundus seems rather underprepared for battle. Its colonies number little more than about 200 individuals and have no more than one or two soldier termites for protection. Even then, they can do little more than block tunnels with their massive heads while the workers flee from an attack.
These puny termites are no match for Coptotermes acinaciformis. They can have colonies of millions with soldiers that can shred the strongest Crytpotermes with a single chomp of their mandibles. In a fight, there’s no doubt who would win. Fortunately, survival isn’t always about who is the strongest, fastest, or biggest. In this war, being sneaky can be enough to save your skin.
Entomologists at CSIRO and the University of New South Wales have discovered that the Cryptotermes termite has an ear for the chewing sounds made by its competitors. When the researchers played recordings of Coptotermes feasting on some splinters, their weaker relatives looked to a quieter block of wood. Faced with such powerful competition, the drywood termite has learned to forage as much food as it can while still keeping a healthy distance from its enemy’s jaws.
For Australians, the drywood termite is less of a problem than the fearless Coptotermes. However, this research could eventually lead to methods for pest control that don’t rely on spraying nasty chemicals. Perhaps it only takes the right tune to send the big ones packing as well?
We often hear the term ‘survival of the fittest’ to describe how natural selection works. In a competition for survival, fitness is simply about finding the best way to get lunch into your belly while avoiding being lunch in somebody else’s.
Illustrated by Mike McRae
Posted in Animals