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Friday, October 2, 2009

How is body heat regulated?

How is body heat regulated?
The thermoregulatory center is composed of two parts. The rostral part is a heat loss center
that is parasympathetic. The caudal part is a heat production center that is sympathetic.
Peripheral thermoreceptors in the skin and internal receptors in the abdomen and central nervous system (eNS) along with the thermoregulatory centers help to maintain a delicate balance between heat loss and production.

What is fever?

What is fever?
Fever is an increased core body temperature due to resetting of the hypothalamic thermoregulatory center to a higher temperature. The thermoregulatory center is located in the preoptic region of the rostral hypothalamus.

Tuesday, August 18, 2009

The Meller's chameleon


is the largest of the chameleons not native to Madagascar. Their stout bodies can grow to be up to two feet (two-thirds of a meter) long and weigh more than a pound (one-half kilogram).
Meller's distinguish themselves from their universally bizarre-looking cousins with a single small horn protruding from the front of their snouts. This and their size earn them the common name "giant one-horned chameleon."
They are fairly common in the savanna of East Africa, including Malawi, northern Mozambique, and Tanzania. Almost one-half of the world’s chameleons live on the island of Madagascar.
As with all chameleons, Meller's will change colors in response to stress and to communicate with other chameleons. Their normal appearance is deep green with yellow stripes and random black spots. Females are slightly smaller, but are otherwise indistinguishable from males.

Saturday, December 27, 2008

Bird of Paradise


There are more than three-dozen species in the family Paradisaeidae, more commonly known as the birds of paradise. Most are distinguished by striking colors and bright plumage of yellow, blue, scarlet, and green. These colors distinguish them as some of the world's most dramatic and attractive birds. Males often sport vibrant feathered ruffs or amazingly elongated feathers, which are known as wires or streamers. Some species have enormous head plumes or other distinctive ornaments, such as breast shields or head fans.

Domestic Cat


Domestic Cat

Domestic cats, no matter their breed, are all members of one species. Felis catus has had a very long relationship with humans. Ancient Egyptians may have first domesticated cats as early as 4,000 years ago. Plentiful rodents probably drew wild felines to human communities. The cats' skill in killing them may have first earned the affectionate attention of humans. Early Egyptians worshipped a cat goddess and even mummified their beloved pets for their journey to the next world—accompanied by mummified mice! Cultures around the world later adopted cats as their own companions.

African Wild Dog

The African wild dog, also called Cape hunting dog or painted dog, typically roams the open plains and sparse woodlands of sub-Saharan Africa.These long-legged canines have only four toes per foot, unlike other dogs, which have five toes on their forefeet. The dog's Latin name means "painted wolf," referring to the animal's irregular, mottled coat, which features patches of red, black, brown, white, and yellow fur. Each animal has its own unique coat pattern, and all have big, rounded ears.African wild dogs live in packs that are usually dominated by a monogamous breeding pair. The female has a litter of 2 to 20 pups, which are cared for by the entire pack. These dogs are very social, and packs have been known to share food and to assist weak or ill members. Social interactions are common, and the dogs communicate by touch, actions, and vocalizations.

Wednesday, June 4, 2008

King Cobra


It seems unfairly menacing that a snake that can literally "stand up" and look a full-grown person in the eye would also be among the most venomous on the planet, but that describes the famous king cobra.King cobras can reach 18 feet (5.5 meters) in length, making them the longest of all venomous snakes. When confronted, they can raise up to one-third of their bodies straight off the ground and still move forward to attack. They will also flare out their iconic hoods and emit a bone-chilling hiss that sounds almost like a growling dog.Their venom is not the most potent among venomous snakes, but the amount of neurotoxin they can deliver in a single bite—up to two-tenths of a fluid ounce (seven milliliters)—is enough to kill 20 people, or even an elephant. Fortunately, king cobras are shy and will avoid humans whenever possible, but they are fiercely aggressive when cornered.King cobras live mainly in the rain forests and plains of India, southern China, and Southeast Asia, and their coloring can vary greatly from region to region. They are comfortable in the trees, on land, and in water, feeding mainly on other snakes, venomous and nonvenomous. They will also eat lizards, eggs, and small mammals.They are the only snakes in the world that build nests for their eggs, which they guard ferociously until the hatchlings emerge.King cobras may be best known as the species of choice for the snake charmers of South Asia. Although cobras can hear, they are actually deaf to ambient noises, sensing ground vibrations instead. The charmer's flute entices the cobra by its shape and movement, not by the music it emits.