Theory: fatter dinosaurs might have survived
May 12, 2008 |17:08 | Animal News | General Information | Land Mammals | Mammals News By : Team X
If dinosaurs had been fatter, they might still be around. That's the theory of a team of researchers at New York Medical College that a lack of heat-generating tissue may have led to the demise of dinosaurs.
Humans, like all mammals, have two kinds of adipose tissue, white fat and brown fat. White fat is used for storing energy-rich fuels, while brown fat generates heat. Hibernating bears have a lot of brown fat, as do human infants, who have much more than adults, relative to their body size. Infants’brown fat protects them from hypothermia.
Clinicians would like to find ways of making adult white fat behave more like brown fat so that we could burn, rather than store, energy.
While most mammals have a key gene called UCP1, which is responsible for the heat-generation function of brown fat, birds do not. The researchers found they could induce a specific type of stem cell in chicken embryos to produce differentiated cells that are structured and behave like brown fat. These chicken cells can even activate a UCP1 gene if presented with one from a mouse.
The ability to produce brown fat evolved in a common ancestor of birds and mammals, but the ability to generate heat was lost in the group that gave rise to birds and lizards after it separated from the mammalian lineage (the researchers found the lizard genome similarly lacks a UCP1 gene). This strongly implies that dinosaurs, which diverged from birds even later than lizards, also lacked brown fat.

The serval cat still was missing Friday afternoon, at least 10 days after escaping the West Michigan Society for the Protection and Care of Animals shelter at 6806 E. Evanston.
When the first duck-billed platypus specimens were sent from Australia to Europe at the end of the 18th century, the bizarre combination of mammal, bird and reptile features led many zoologists to consider them a hoax. 
Alaska Native and environmental groups sued Monday to stop exploration by oil companies this summer in Arctic waters frequented by whales, seals and other marine species.
A team of Filipino and American scientists have rediscovered a highly distinctive mammal a greater dwarf cloud rat that was last seen 112 years ago. Furthermore, it has never before been discovered in its natural habitat and was thought by some to be extinct.The greater dwarf cloud rat (Carpomys melanurus) has dense, soft reddish-brown fur, a black mask around large dark eyes, small rounded ears, a broad and blunt snout, and a long tail covered with dark hair. An adult weighs about 185 grams.
The narwhal, a strange cetacean with a long tusk unicorn-like at the end of its snout, depends on cod, which live under ice-enclosed seas. The also narwhals spend winters amid the sea ice, which helps them to avoid predators like the orca. Currently, the population of narwhals is unknown, but they are not a common sight in Arctic waters.
Some of the patients were orphaned. Others were injured after being hit by boats. Ten are in critical condition.
The loss of sea ice due to climate change could spell disaster for polar bears and other Arctic marine mammals. Sea ice is the common habitat feature uniting these unique and diverse Arctic inhabitants. Sea ice serves as a platform for resting and reproduction, influences the distribution of food sources, and provides a refuge from predators. The loss of sea ice poses a particularly severe threat to Arctic species, such as the hooded seal, whose natural history is closely tied to, and depends on, sea ice.
Twenty-seven kittens, ranging from blind newborns to fluffy 12-week-olds, snuggled and played in cages at the Floyd County Animal Control shelter Friday, oblivious to their fate. 








